From beda2c7ea2c15ed01eef00a997d2b0496c3a502d Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Sun, 9 Aug 2009 15:34:39 -0700 Subject: futex: Update futex_q lock_ptr on requeue proxy lock futex_requeue() can acquire the lock on behalf of a waiter early on or during the requeue loop if it is uncontended or in the event of a lock steal or owner died. On wakeup, the waiter (in futex_wait_requeue_pi()) cleans up the pi_state owner using the lock_ptr to protect against concurrent access to the pi_state. The pi_state is hung off futex_q's on the requeue target futex hash bucket so the lock_ptr needs to be updated accordingly. The problem manifested by triggering the WARN_ON in lookup_pi_state() about the pid != pi_state->owner->pid. With this patch, the pi_state is properly guarded against concurrent access via the requeue target hb lock. The astute reviewer may notice that there is a window of time between when futex_requeue() unlocks the hb locks and when futex_wait_requeue_pi() will acquire hb2->lock. During this time the pi_state and uval are not in sync with the underlying rtmutex owner (but the uval does indicate there are waiters, so no atomic changes will occur in userspace). However, this is not a problem. Should a contending thread enter lookup_pi_state() and acquire hb2->lock before the ownership is fixed up, it will find the pi_state hung off a waiter's (possibly the pending owner's) futex_q and block on the rtmutex. Once futex_wait_requeue_pi() fixes up the owner, it will also move the pi_state from the old owner's task->pi_state_list to its own. v3: Fix plist lock name for application to mainline (rather than -rt) Compile tested against tip/v2.6.31-rc5. Signed-off-by: Darren Hart Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Eric Dumazet Cc: Dinakar Guniguntala Cc: John Stultz LKML-Reference: <4A7F4EFF.6090903@us.ibm.com> Signed-off-by: Ingo Molnar --- kernel/futex.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 0672ff8..8cc3ee1 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1010,15 +1010,19 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1, * requeue_pi_wake_futex() - Wake a task that acquired the lock during requeue * q: the futex_q * key: the key of the requeue target futex + * hb: the hash_bucket of the requeue target futex * * During futex_requeue, with requeue_pi=1, it is possible to acquire the * target futex if it is uncontended or via a lock steal. Set the futex_q key * to the requeue target futex so the waiter can detect the wakeup on the right * futex, but remove it from the hb and NULL the rt_waiter so it can detect - * atomic lock acquisition. Must be called with the q->lock_ptr held. + * atomic lock acquisition. Set the q->lock_ptr to the requeue target hb->lock + * to protect access to the pi_state to fixup the owner later. Must be called + * with both q->lock_ptr and hb->lock held. */ static inline -void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key) +void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, + struct futex_hash_bucket *hb) { drop_futex_key_refs(&q->key); get_futex_key_refs(key); @@ -1030,6 +1034,11 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key) WARN_ON(!q->rt_waiter); q->rt_waiter = NULL; + q->lock_ptr = &hb->lock; +#ifdef CONFIG_DEBUG_PI_LIST + q->list.plist.lock = &hb->lock; +#endif + wake_up_state(q->task, TASK_NORMAL); } @@ -1088,7 +1097,7 @@ static int futex_proxy_trylock_atomic(u32 __user *pifutex, ret = futex_lock_pi_atomic(pifutex, hb2, key2, ps, top_waiter->task, set_waiters); if (ret == 1) - requeue_pi_wake_futex(top_waiter, key2); + requeue_pi_wake_futex(top_waiter, key2, hb2); return ret; } @@ -1273,7 +1282,7 @@ retry_private: this->task, 1); if (ret == 1) { /* We got the lock. */ - requeue_pi_wake_futex(this, &key2); + requeue_pi_wake_futex(this, &key2, hb2); continue; } else if (ret) { /* -EDEADLK */ -- cgit v1.1 From 2fc391112fb6f3424435a3aa2fda887497b5f807 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 10 Aug 2009 12:33:05 +0100 Subject: locking, sched: Give waitqueue spinlocks their own lockdep classes Give waitqueue spinlocks their own lockdep classes when they are initialised from init_waitqueue_head(). This means that struct wait_queue::func functions can operate other waitqueues. This is used by CacheFiles to catch the page from a backing fs being unlocked and to wake up another thread to take a copy of it. Signed-off-by: Peter Zijlstra Signed-off-by: David Howells Tested-by: Takashi Iwai Cc: linux-cachefs@redhat.com Cc: torvalds@osdl.org Cc: akpm@linux-foundation.org LKML-Reference: <20090810113305.17284.81508.stgit@warthog.procyon.org.uk> Signed-off-by: Ingo Molnar --- kernel/wait.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/wait.c b/kernel/wait.c index ea7c3b4..c4bd3d8 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -10,13 +10,14 @@ #include #include -void init_waitqueue_head(wait_queue_head_t *q) +void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *key) { spin_lock_init(&q->lock); + lockdep_set_class(&q->lock, key); INIT_LIST_HEAD(&q->task_list); } -EXPORT_SYMBOL(init_waitqueue_head); +EXPORT_SYMBOL(__init_waitqueue_head); void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait) { -- cgit v1.1 From 4dc88029fd916b860ef063c40180aa604ce93494 Mon Sep 17 00:00:00 2001 From: Dinakar Guniguntala Date: Mon, 10 Aug 2009 18:31:42 +0530 Subject: futex: Fix compat_futex to be same as futex for REQUEUE_PI Need to add the REQUEUE_PI checks to the compat_sys_futex API as well to ensure 32 bit requeue's work fine on a 64 bit system. Patch is against latest tip Signed-off-by: Dinakar Guniguntala Cc: Darren Hart LKML-Reference: <20090810130142.GA23619@in.ibm.com> Signed-off-by: Ingo Molnar --- kernel/futex_compat.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c index d607a5b..2357165 100644 --- a/kernel/futex_compat.c +++ b/kernel/futex_compat.c @@ -180,7 +180,8 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val, int cmd = op & FUTEX_CMD_MASK; if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI || - cmd == FUTEX_WAIT_BITSET)) { + cmd == FUTEX_WAIT_BITSET || + cmd == FUTEX_WAIT_REQUEUE_PI)) { if (get_compat_timespec(&ts, utime)) return -EFAULT; if (!timespec_valid(&ts)) @@ -191,7 +192,8 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val, t = ktime_add_safe(ktime_get(), t); tp = &t; } - if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE) + if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE || + cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP) val2 = (int) (unsigned long) utime; return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); -- cgit v1.1 From 392741e0a4e17c82e3978b7fcbf04291294dc0a1 Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Fri, 7 Aug 2009 15:20:48 -0700 Subject: futex: Fix handling of bad requeue syscall pairing If futex_requeue(requeue_pi=1) finds a futex_q that was created by a call other the futex_wait_requeue_pi(), the q.rt_waiter may be null. If so, this will result in an oops from the following call graph: futex_requeue() rt_mutex_start_proxy_lock() task_blocks_on_rt_mutex() waiter->task dereference OOPS We currently WARN_ON() if this is detected, clearly this is inadequate. If we detect a mispairing in futex_requeue(), bail out, seding -EINVAL to user-space. V2: Fix parenthesis warnings. Signed-off-by: Darren Hart Acked-by: Peter Zijlstra Cc: Steven Rostedt Cc: John Kacur Cc: Eric Dumazet Cc: Dinakar Guniguntala Cc: John Stultz LKML-Reference: <4A7CA8C0.7010809@us.ibm.com> Signed-off-by: Ingo Molnar --- kernel/futex.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 8cc3ee1..e18cfbd 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1256,8 +1256,15 @@ retry_private: if (!match_futex(&this->key, &key1)) continue; - WARN_ON(!requeue_pi && this->rt_waiter); - WARN_ON(requeue_pi && !this->rt_waiter); + /* + * FUTEX_WAIT_REQEUE_PI and FUTEX_CMP_REQUEUE_PI should always + * be paired with each other and no other futex ops. + */ + if ((requeue_pi && !this->rt_waiter) || + (!requeue_pi && this->rt_waiter)) { + ret = -EINVAL; + break; + } /* * Wake nr_wake waiters. For requeue_pi, if we acquired the -- cgit v1.1 From 39cbb602b543e477df71dca84b5b2e36f8bd29fc Mon Sep 17 00:00:00 2001 From: "Alan D. Brunelle" Date: Fri, 7 Aug 2009 12:01:08 -0400 Subject: Remove double removal of blktrace directory commit fd51d251e4cdb21f68e9dbc4336514d64a105a79 Author: Stefan Raspl Date: Tue May 19 09:59:08 2009 +0200 blktrace: remove debugfs entries on bad path added in an explicit invocation of debugfs_remove for bt->dir, in blk_remove_buf_file_callback we are also getting the directory removed. On occasion I am seeing memory corruption that I have bisected down to this commit. [The testing involves a (long) series of I/O benchmarks with blktrace invoked around the actual runs.] I believe that this committed patch is correct, but the problem actually lies in the code in blk_remove_buf_file_callback. With this patch I am able to consistently get complete runs whereas previously I could not get a single run to complete. The first part of the patch simply moves the debugfs_remove below the relay_close: the relay_close call will remove files under bt->dir, and so we should not remove the directory until all the files we created have been removed. (Note: This is not sufficient to fix the problem - the file system code has ref counts on the directoy, so our invocation does not cause the directory to actually be removed. Nonetheless, we should not rely upon that feature.) Signed-off-by: Alan D. Brunelle Signed-off-by: Jens Axboe --- kernel/trace/blktrace.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 1090b0a..7a34cb5 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -267,8 +267,8 @@ static void blk_trace_free(struct blk_trace *bt) { debugfs_remove(bt->msg_file); debugfs_remove(bt->dropped_file); - debugfs_remove(bt->dir); relay_close(bt->rchan); + debugfs_remove(bt->dir); free_percpu(bt->sequence); free_percpu(bt->msg_data); kfree(bt); @@ -378,18 +378,8 @@ static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, static int blk_remove_buf_file_callback(struct dentry *dentry) { - struct dentry *parent = dentry->d_parent; debugfs_remove(dentry); - /* - * this will fail for all but the last file, but that is ok. what we - * care about is the top level buts->name directory going away, when - * the last trace file is gone. Then we don't have to rmdir() that - * manually on trace stop, so it nicely solves the issue with - * force killing of running traces. - */ - - debugfs_remove(parent); return 0; } -- cgit v1.1 From 28402971d869e26271b25301011f667d3a5640c3 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 13 Aug 2009 10:13:22 +0200 Subject: perf_counter: Provide hw_perf_counter_setup_online() APIs Provide weak aliases for hw_perf_counter_setup_online(). This is used by the BTS patches (for v2.6.32), but it interacts with fixes so propagate this upstream. (it has no effect as of yet) Also export perf_counter_output() to architecture code. Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index b0b20a0..e26d2fc 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -88,6 +88,7 @@ void __weak hw_perf_disable(void) { barrier(); } void __weak hw_perf_enable(void) { barrier(); } void __weak hw_perf_counter_setup(int cpu) { barrier(); } +void __weak hw_perf_counter_setup_online(int cpu) { barrier(); } int __weak hw_perf_group_sched_in(struct perf_counter *group_leader, @@ -2630,7 +2631,7 @@ static u32 perf_counter_tid(struct perf_counter *counter, struct task_struct *p) return task_pid_nr_ns(p, counter->ns); } -static void perf_counter_output(struct perf_counter *counter, int nmi, +void perf_counter_output(struct perf_counter *counter, int nmi, struct perf_sample_data *data) { int ret; @@ -4592,6 +4593,11 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) perf_counter_init_cpu(cpu); break; + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + hw_perf_counter_setup_online(cpu); + break; + case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: perf_counter_exit_cpu(cpu); @@ -4616,6 +4622,8 @@ void __init perf_counter_init(void) { perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE, (void *)(long)smp_processor_id()); + perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE, + (void *)(long)smp_processor_id()); register_cpu_notifier(&perf_cpu_nb); } -- cgit v1.1 From bcfc2602e8541ac13b1def38e2591dca072cff7a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 13 Aug 2009 09:51:55 +0200 Subject: perf_counter: Fix swcounter context invariance perf_swcounter_is_counting() uses a lock, which means we cannot use swcounters from NMI or when holding that particular lock, this is unintended. The below removes the lock, this opens up race window, but not worse than the swcounters already experience due to RCU traversal of the context in perf_swcounter_ctx_event(). This also fixes the hard lockups while opening a lockdep tracepoint counter. Signed-off-by: Peter Zijlstra Acked-by: Frederic Weisbecker Cc: Paul Mackerras Cc: stephane eranian Cc: Corey J Ashford LKML-Reference: <1250149915.10001.66.camel@twins> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 44 ++++++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index e26d2fc..3dd4339 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -3444,40 +3444,32 @@ static void perf_swcounter_add(struct perf_counter *counter, u64 nr, static int perf_swcounter_is_counting(struct perf_counter *counter) { - struct perf_counter_context *ctx; - unsigned long flags; - int count; - + /* + * The counter is active, we're good! + */ if (counter->state == PERF_COUNTER_STATE_ACTIVE) return 1; + /* + * The counter is off/error, not counting. + */ if (counter->state != PERF_COUNTER_STATE_INACTIVE) return 0; /* - * If the counter is inactive, it could be just because - * its task is scheduled out, or because it's in a group - * which could not go on the PMU. We want to count in - * the first case but not the second. If the context is - * currently active then an inactive software counter must - * be the second case. If it's not currently active then - * we need to know whether the counter was active when the - * context was last active, which we can determine by - * comparing counter->tstamp_stopped with ctx->time. - * - * We are within an RCU read-side critical section, - * which protects the existence of *ctx. + * The counter is inactive, if the context is active + * we're part of a group that didn't make it on the 'pmu', + * not counting. */ - ctx = counter->ctx; - spin_lock_irqsave(&ctx->lock, flags); - count = 1; - /* Re-check state now we have the lock */ - if (counter->state < PERF_COUNTER_STATE_INACTIVE || - counter->ctx->is_active || - counter->tstamp_stopped < ctx->time) - count = 0; - spin_unlock_irqrestore(&ctx->lock, flags); - return count; + if (counter->ctx->is_active) + return 0; + + /* + * We're inactive and the context is too, this means the + * task is scheduled out, we're counting events that happen + * to us, like migration events. + */ + return 1; } static int perf_swcounter_match(struct perf_counter *counter, -- cgit v1.1 From 3dab77fb1bf89664bb1c9544607159dcab6f7d57 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 13 Aug 2009 11:47:53 +0200 Subject: perf: Rework/fix the whole read vs group stuff Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce PERF_FORMAT_GROUP to deal with group reads in a more generic way. This allows you to get group reads out of read() as well. Signed-off-by: Peter Zijlstra Cc: Corey J Ashford Cc: Paul Mackerras Cc: stephane eranian LKML-Reference: <20090813103655.117411814@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 274 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 202 insertions(+), 72 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 3dd4339..b8c6b97 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1692,7 +1692,32 @@ static int perf_release(struct inode *inode, struct file *file) return 0; } -static u64 perf_counter_read_tree(struct perf_counter *counter) +static int perf_counter_read_size(struct perf_counter *counter) +{ + int entry = sizeof(u64); /* value */ + int size = 0; + int nr = 1; + + if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + size += sizeof(u64); + + if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + size += sizeof(u64); + + if (counter->attr.read_format & PERF_FORMAT_ID) + entry += sizeof(u64); + + if (counter->attr.read_format & PERF_FORMAT_GROUP) { + nr += counter->group_leader->nr_siblings; + size += sizeof(u64); + } + + size += entry * nr; + + return size; +} + +static u64 perf_counter_read_value(struct perf_counter *counter) { struct perf_counter *child; u64 total = 0; @@ -1704,14 +1729,96 @@ static u64 perf_counter_read_tree(struct perf_counter *counter) return total; } +static int perf_counter_read_entry(struct perf_counter *counter, + u64 read_format, char __user *buf) +{ + int n = 0, count = 0; + u64 values[2]; + + values[n++] = perf_counter_read_value(counter); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_counter_id(counter); + + count = n * sizeof(u64); + + if (copy_to_user(buf, values, count)) + return -EFAULT; + + return count; +} + +static int perf_counter_read_group(struct perf_counter *counter, + u64 read_format, char __user *buf) +{ + struct perf_counter *leader = counter->group_leader, *sub; + int n = 0, size = 0, err = -EFAULT; + u64 values[3]; + + values[n++] = 1 + leader->nr_siblings; + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { + values[n++] = leader->total_time_enabled + + atomic64_read(&leader->child_total_time_enabled); + } + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { + values[n++] = leader->total_time_running + + atomic64_read(&leader->child_total_time_running); + } + + size = n * sizeof(u64); + + if (copy_to_user(buf, values, size)) + return -EFAULT; + + err = perf_counter_read_entry(leader, read_format, buf + size); + if (err < 0) + return err; + + size += err; + + list_for_each_entry(sub, &leader->sibling_list, list_entry) { + err = perf_counter_read_entry(counter, read_format, + buf + size); + if (err < 0) + return err; + + size += err; + } + + return size; +} + +static int perf_counter_read_one(struct perf_counter *counter, + u64 read_format, char __user *buf) +{ + u64 values[4]; + int n = 0; + + values[n++] = perf_counter_read_value(counter); + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { + values[n++] = counter->total_time_enabled + + atomic64_read(&counter->child_total_time_enabled); + } + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { + values[n++] = counter->total_time_running + + atomic64_read(&counter->child_total_time_running); + } + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_counter_id(counter); + + if (copy_to_user(buf, values, n * sizeof(u64))) + return -EFAULT; + + return n * sizeof(u64); +} + /* * Read the performance counter - simple non blocking version for now */ static ssize_t perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count) { - u64 values[4]; - int n; + u64 read_format = counter->attr.read_format; + int ret; /* * Return end-of-file for a read on a counter that is in @@ -1721,28 +1828,18 @@ perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count) if (counter->state == PERF_COUNTER_STATE_ERROR) return 0; + if (count < perf_counter_read_size(counter)) + return -ENOSPC; + WARN_ON_ONCE(counter->ctx->parent_ctx); mutex_lock(&counter->child_mutex); - values[0] = perf_counter_read_tree(counter); - n = 1; - if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) - values[n++] = counter->total_time_enabled + - atomic64_read(&counter->child_total_time_enabled); - if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) - values[n++] = counter->total_time_running + - atomic64_read(&counter->child_total_time_running); - if (counter->attr.read_format & PERF_FORMAT_ID) - values[n++] = primary_counter_id(counter); + if (read_format & PERF_FORMAT_GROUP) + ret = perf_counter_read_group(counter, read_format, buf); + else + ret = perf_counter_read_one(counter, read_format, buf); mutex_unlock(&counter->child_mutex); - if (count < n * sizeof(u64)) - return -EINVAL; - count = n * sizeof(u64); - - if (copy_to_user(buf, values, count)) - return -EFAULT; - - return count; + return ret; } static ssize_t @@ -2631,6 +2728,79 @@ static u32 perf_counter_tid(struct perf_counter *counter, struct task_struct *p) return task_pid_nr_ns(p, counter->ns); } +static void perf_output_read_one(struct perf_output_handle *handle, + struct perf_counter *counter) +{ + u64 read_format = counter->attr.read_format; + u64 values[4]; + int n = 0; + + values[n++] = atomic64_read(&counter->count); + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { + values[n++] = counter->total_time_enabled + + atomic64_read(&counter->child_total_time_enabled); + } + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { + values[n++] = counter->total_time_running + + atomic64_read(&counter->child_total_time_running); + } + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_counter_id(counter); + + perf_output_copy(handle, values, n * sizeof(u64)); +} + +/* + * XXX PERF_FORMAT_GROUP vs inherited counters seems difficult. + */ +static void perf_output_read_group(struct perf_output_handle *handle, + struct perf_counter *counter) +{ + struct perf_counter *leader = counter->group_leader, *sub; + u64 read_format = counter->attr.read_format; + u64 values[5]; + int n = 0; + + values[n++] = 1 + leader->nr_siblings; + + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) + values[n++] = leader->total_time_enabled; + + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) + values[n++] = leader->total_time_running; + + if (leader != counter) + leader->pmu->read(leader); + + values[n++] = atomic64_read(&leader->count); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_counter_id(leader); + + perf_output_copy(handle, values, n * sizeof(u64)); + + list_for_each_entry(sub, &leader->sibling_list, list_entry) { + n = 0; + + if (sub != counter) + sub->pmu->read(sub); + + values[n++] = atomic64_read(&sub->count); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_counter_id(sub); + + perf_output_copy(handle, values, n * sizeof(u64)); + } +} + +static void perf_output_read(struct perf_output_handle *handle, + struct perf_counter *counter) +{ + if (counter->attr.read_format & PERF_FORMAT_GROUP) + perf_output_read_group(handle, counter); + else + perf_output_read_one(handle, counter); +} + void perf_counter_output(struct perf_counter *counter, int nmi, struct perf_sample_data *data) { @@ -2642,10 +2812,6 @@ void perf_counter_output(struct perf_counter *counter, int nmi, struct { u32 pid, tid; } tid_entry; - struct { - u64 id; - u64 counter; - } group_entry; struct perf_callchain_entry *callchain = NULL; int callchain_size = 0; u64 time; @@ -2700,10 +2866,8 @@ void perf_counter_output(struct perf_counter *counter, int nmi, if (sample_type & PERF_SAMPLE_PERIOD) header.size += sizeof(u64); - if (sample_type & PERF_SAMPLE_GROUP) { - header.size += sizeof(u64) + - counter->nr_siblings * sizeof(group_entry); - } + if (sample_type & PERF_SAMPLE_READ) + header.size += perf_counter_read_size(counter); if (sample_type & PERF_SAMPLE_CALLCHAIN) { callchain = perf_callchain(data->regs); @@ -2760,26 +2924,8 @@ void perf_counter_output(struct perf_counter *counter, int nmi, if (sample_type & PERF_SAMPLE_PERIOD) perf_output_put(&handle, data->period); - /* - * XXX PERF_SAMPLE_GROUP vs inherited counters seems difficult. - */ - if (sample_type & PERF_SAMPLE_GROUP) { - struct perf_counter *leader, *sub; - u64 nr = counter->nr_siblings; - - perf_output_put(&handle, nr); - - leader = counter->group_leader; - list_for_each_entry(sub, &leader->sibling_list, list_entry) { - if (sub != counter) - sub->pmu->read(sub); - - group_entry.id = primary_counter_id(sub); - group_entry.counter = atomic64_read(&sub->count); - - perf_output_put(&handle, group_entry); - } - } + if (sample_type & PERF_SAMPLE_READ) + perf_output_read(&handle, counter); if (sample_type & PERF_SAMPLE_CALLCHAIN) { if (callchain) @@ -2818,8 +2964,6 @@ struct perf_read_event { u32 pid; u32 tid; - u64 value; - u64 format[3]; }; static void @@ -2831,34 +2975,20 @@ perf_counter_read_event(struct perf_counter *counter, .header = { .type = PERF_EVENT_READ, .misc = 0, - .size = sizeof(event) - sizeof(event.format), + .size = sizeof(event) + perf_counter_read_size(counter), }, .pid = perf_counter_pid(counter, task), .tid = perf_counter_tid(counter, task), - .value = atomic64_read(&counter->count), }; - int ret, i = 0; - - if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { - event.header.size += sizeof(u64); - event.format[i++] = counter->total_time_enabled; - } - - if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { - event.header.size += sizeof(u64); - event.format[i++] = counter->total_time_running; - } - - if (counter->attr.read_format & PERF_FORMAT_ID) { - event.header.size += sizeof(u64); - event.format[i++] = primary_counter_id(counter); - } + int ret; ret = perf_output_begin(&handle, counter, event.header.size, 0, 0); if (ret) return; - perf_output_copy(&handle, &event, event.header.size); + perf_output_put(&handle, event); + perf_output_read(&handle, counter); + perf_output_end(&handle); } @@ -3921,9 +4051,9 @@ perf_counter_alloc(struct perf_counter_attr *attr, atomic64_set(&hwc->period_left, hwc->sample_period); /* - * we currently do not support PERF_SAMPLE_GROUP on inherited counters + * we currently do not support PERF_FORMAT_GROUP on inherited counters */ - if (attr->inherit && (attr->sample_type & PERF_SAMPLE_GROUP)) + if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) goto done; switch (attr->type) { -- cgit v1.1 From 970892a9031a5dc7217bd394fb9d89fa75a4a7bc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 13 Aug 2009 11:47:54 +0200 Subject: perf_counter: Fix an ipi-deadlock perf_pending_counter() is called from IRQ context and will call perf_counter_disable(), however perf_counter_disable() uses smp_call_function_single() which doesn't fancy being used with IRQs disabled due to IPI deadlocks. Fix this by making it use the local __perf_counter_disable() call and teaching the counter_sched_out() code about pending disables as well. This should cover the case where a counter migrates before the pending queue gets processed. Signed-off-by: Peter Zijlstra Cc: Corey J Ashford Cc: Paul Mackerras Cc: stephane eranian LKML-Reference: <20090813103655.244097721@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index b8c6b97..3f841be 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -307,6 +307,10 @@ counter_sched_out(struct perf_counter *counter, return; counter->state = PERF_COUNTER_STATE_INACTIVE; + if (counter->pending_disable) { + counter->pending_disable = 0; + counter->state = PERF_COUNTER_STATE_OFF; + } counter->tstamp_stopped = ctx->time; counter->pmu->disable(counter); counter->oncpu = -1; @@ -2343,7 +2347,7 @@ static void perf_pending_counter(struct perf_pending_entry *entry) if (counter->pending_disable) { counter->pending_disable = 0; - perf_counter_disable(counter); + __perf_counter_disable(counter); } if (counter->pending_wakeup) { -- cgit v1.1 From 94d5d1b2d891f1fd5205f978246b7864d998b25c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 13 Aug 2009 16:14:42 +0200 Subject: perf_counter: Report the cloning task as parent on perf_counter_fork() A bug in (9f498cc: perf_counter: Full task tracing) makes profiling multi-threaded apps it go belly up. [ output as: (PID:TID):(PPID:PTID) ] # ./perf report -D | grep FORK 0x4b0 [0x18]: PERF_EVENT_FORK: (3237:3237):(3236:3236) 0xa10 [0x18]: PERF_EVENT_FORK: (3237:3238):(3236:3236) 0xa70 [0x18]: PERF_EVENT_FORK: (3237:3239):(3236:3236) 0xad0 [0x18]: PERF_EVENT_FORK: (3237:3240):(3236:3236) 0xb18 [0x18]: PERF_EVENT_FORK: (3237:3241):(3236:3236) Shows us that the test (27d028d perf report: Update for the new FORK/EXIT events) in builtin-report.c: /* * A thread clone will have the same PID for both * parent and child. */ if (thread == parent) return 0; Will clearly fail. The problem is that perf_counter_fork() reports the actual parent, instead of the cloning thread. Fixing that (with the below patch), yields: # ./perf report -D | grep FORK 0x4c8 [0x18]: PERF_EVENT_FORK: (1590:1590):(1589:1589) 0xbd8 [0x18]: PERF_EVENT_FORK: (1590:1591):(1590:1590) 0xc80 [0x18]: PERF_EVENT_FORK: (1590:1592):(1590:1590) 0x3338 [0x18]: PERF_EVENT_FORK: (1590:1593):(1590:1590) 0x66b0 [0x18]: PERF_EVENT_FORK: (1590:1594):(1590:1590) Which both makes more sense and doesn't confuse perf report anymore. Reported-by: Pekka Enberg Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: paulus@samba.org Cc: Anton Blanchard Cc: Arjan van de Ven LKML-Reference: <1250172882.5241.62.camel@twins> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 3f841be..534e20d 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -3028,10 +3028,10 @@ static void perf_counter_task_output(struct perf_counter *counter, return; task_event->event.pid = perf_counter_pid(counter, task); - task_event->event.ppid = perf_counter_pid(counter, task->real_parent); + task_event->event.ppid = perf_counter_pid(counter, current); task_event->event.tid = perf_counter_tid(counter, task); - task_event->event.ptid = perf_counter_tid(counter, task->real_parent); + task_event->event.ptid = perf_counter_tid(counter, current); perf_output_put(&handle, task_event->event); perf_output_end(&handle); -- cgit v1.1 From 2d860ad76f4ee4d2eba0fe3797c8d7cdce432cc0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 13 Aug 2009 13:05:10 -0700 Subject: genirq: prevent wakeup of freed irq thread free_irq() can remove an irqaction while the corresponding interrupt is in progress, but free_irq() sets action->thread to NULL unconditionally, which might lead to a NULL pointer dereference in handle_IRQ_event() when the hard interrupt context tries to wake up the handler thread. Prevent this by moving the thread stop after synchronize_irq(). No need to set action->thread to NULL either as action is going to be freed anyway. This fixes a boot crash reported against preempt-rt which uses the mainline irq threads code to implement full irq threading. [ tglx: removed local irqthread variable ] Signed-off-by: Linus Torvalds Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 61c679d..d222515 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -761,7 +761,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) { struct irq_desc *desc = irq_to_desc(irq); struct irqaction *action, **action_ptr; - struct task_struct *irqthread; unsigned long flags; WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq); @@ -809,9 +808,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) desc->chip->disable(irq); } - irqthread = action->thread; - action->thread = NULL; - spin_unlock_irqrestore(&desc->lock, flags); unregister_handler_proc(irq, action); @@ -819,12 +815,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) /* Make sure it's not being used on another CPU: */ synchronize_irq(irq); - if (irqthread) { - if (!test_bit(IRQTF_DIED, &action->thread_flags)) - kthread_stop(irqthread); - put_task_struct(irqthread); - } - #ifdef CONFIG_DEBUG_SHIRQ /* * It's a shared IRQ -- the driver ought to be prepared for an IRQ @@ -840,6 +830,13 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) local_irq_restore(flags); } #endif + + if (action->thread) { + if (!test_bit(IRQTF_DIED, &action->thread_flags)) + kthread_stop(action->thread); + put_task_struct(action->thread); + } + return action; } -- cgit v1.1 From 788084aba2ab7348257597496befcbccabdc98a3 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Fri, 31 Jul 2009 12:54:11 -0400 Subject: Security/SELinux: seperate lsm specific mmap_min_addr Currently SELinux enforcement of controls on the ability to map low memory is determined by the mmap_min_addr tunable. This patch causes SELinux to ignore the tunable and instead use a seperate Kconfig option specific to how much space the LSM should protect. The tunable will now only control the need for CAP_SYS_RAWIO and SELinux permissions will always protect the amount of low memory designated by CONFIG_LSM_MMAP_MIN_ADDR. This allows users who need to disable the mmap_min_addr controls (usual reason being they run WINE as a non-root user) to do so and still have SELinux controls preventing confined domains (like a web server) from being able to map some area of low memory. Signed-off-by: Eric Paris Signed-off-by: James Morris --- kernel/sysctl.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 98e0232..58be760 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -49,6 +49,7 @@ #include #include #include +#include #include #include @@ -1306,10 +1307,10 @@ static struct ctl_table vm_table[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "mmap_min_addr", - .data = &mmap_min_addr, - .maxlen = sizeof(unsigned long), + .data = &dac_mmap_min_addr, + .maxlen = sizeof(unsigned long), .mode = 0644, - .proc_handler = &proc_doulongvec_minmax, + .proc_handler = &mmap_min_addr_handler, }, #ifdef CONFIG_NUMA { -- cgit v1.1 From e1ac3614ff606ae03677f47459113f98a19af63c Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Fri, 14 Aug 2009 15:39:10 +1000 Subject: perf_counter: Check task on counter read IPI In general, code in perf_counter.c that is called through an IPI checks, for per-task counters, that the counter's task is still the current task. This is to handle the race condition where the cpu switches from the task we want to another task in the interval between sending the IPI and the IPI arriving and being handled on the target CPU. For some reason, __perf_counter_read is missing this check, yet there is no reason why the race condition can't occur. This adds a check that the current task is the one we want. If it isn't, we just return. In that case the counter->count value should be up to date, since it will have been updated when the counter was scheduled out, which must have happened since the IPI was sent. I don't have an example of an actual failure due to this race, but it seems obvious that it could occur and we need to guard against it. Signed-off-by: Paul Mackerras Acked-by: Peter Zijlstra LKML-Reference: <19076.63614.277861.368125@drongo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 534e20d..b8fe739 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1503,10 +1503,21 @@ static void perf_counter_enable_on_exec(struct task_struct *task) */ static void __perf_counter_read(void *info) { + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_counter *counter = info; struct perf_counter_context *ctx = counter->ctx; unsigned long flags; + /* + * If this is a task context, we need to check whether it is + * the current task context of this cpu. If not it has been + * scheduled out before the smp call arrived. In that case + * counter->count would have been updated to a recent sample + * when the counter was scheduled out. + */ + if (ctx->task && cpuctx->task_ctx != ctx) + return; + local_irq_save(flags); if (ctx->is_active) update_context_time(ctx); -- cgit v1.1 From de809347aeef0a68c04576c464414d0e4dce59fc Mon Sep 17 00:00:00 2001 From: Amerigo Wang Date: Mon, 17 Aug 2009 05:43:01 -0400 Subject: timers: Drop write permission on /proc/timer_list /proc/timer_list and /proc/slabinfo are not supposed to be written, so there should be no write permissions on it. Signed-off-by: WANG Cong Cc: Pekka Enberg Cc: Vegard Nossum Cc: Eduard - Gabriel Munteanu Cc: linux-mm@kvack.org Cc: Christoph Lameter Cc: David Rientjes Cc: Amerigo Wang Cc: Matt Mackall Cc: Arjan van de Ven LKML-Reference: <20090817094525.6355.88682.sendpatchset@localhost.localdomain> Signed-off-by: Ingo Molnar --- kernel/time/timer_list.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index a999b92..fddd69d 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -286,7 +286,7 @@ static int __init init_timer_list_procfs(void) { struct proc_dir_entry *pe; - pe = proc_create("timer_list", 0644, NULL, &timer_list_fops); + pe = proc_create("timer_list", 0444, NULL, &timer_list_fops); if (!pe) return -ENOMEM; return 0; -- cgit v1.1 From f2d84b65b9778e8a35dd904f7d3993f0a60c9756 Mon Sep 17 00:00:00 2001 From: Zhaolei Date: Fri, 7 Aug 2009 18:55:48 +0800 Subject: ftrace: Unify effect of writing to trace_options and option/* "echo noglobal-clock > trace_options" can be used to change trace clock but "echo 0 > options/global-clock" can't. The flag toggling will be silently accepted without actually changing the clock callback. We can fix it by using set_tracer_flags() in trace_options_core_write(). Changelog: v1->v2: Simplified switch() after Li Zefan 's suggestion Signed-off-by: Zhao Lei Cc: Steven Rostedt Cc: Li Zefan Signed-off-by: Frederic Weisbecker --- kernel/trace/trace.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c22b40f..8c35839 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3896,17 +3896,9 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt, if (ret < 0) return ret; - switch (val) { - case 0: - trace_flags &= ~(1 << index); - break; - case 1: - trace_flags |= 1 << index; - break; - - default: + if (val != 0 && val != 1) return -EINVAL; - } + set_tracer_flags(1 << index, val); *ppos += cnt; -- cgit v1.1 From f738eb1b63edf664da1b4ac76895d988749b2f07 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 18 Aug 2009 11:32:24 +0200 Subject: perf_counter: Fix the PARISC build PARISC does not build: /home/mingo/tip/kernel/perf_counter.c: In function 'perf_counter_index': /home/mingo/tip/kernel/perf_counter.c:2016: error: 'PERF_COUNTER_INDEX_OFFSET' undeclared (first use in this function) /home/mingo/tip/kernel/perf_counter.c:2016: error: (Each undeclared identifier is reported only once /home/mingo/tip/kernel/perf_counter.c:2016: error: for each function it appears in.) As PERF_COUNTER_INDEX_OFFSET is not defined. Now, we could define it in the architecture - but lets also provide a core default of 0 (which happens to be what all but one architecture uses at the moment). Architectures that need a different index offset should set this value in their asm/perf_counter.h files. Cc: Kyle McMartin Cc: Helge Deller Cc: linux-parisc@vger.kernel.org Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index b8fe739..36f65e2 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -2019,6 +2019,10 @@ int perf_counter_task_disable(void) return 0; } +#ifndef PERF_COUNTER_INDEX_OFFSET +# define PERF_COUNTER_INDEX_OFFSET 0 +#endif + static int perf_counter_index(struct perf_counter *counter) { if (counter->state != PERF_COUNTER_STATE_ACTIVE) -- cgit v1.1 From 69ab849439b506cd8dd2879527fdb64d95dd5211 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 17 Aug 2009 14:07:16 +0200 Subject: genirq: Wake up irq thread after action has been installed The wake_up_process() of the new irq thread in __setup_irq() is too early as the irqaction is not yet fully initialized especially action->irq is not yet set. The interrupt thread might dereference the wrong irq descriptor. Move the wakeup after the action is installed and action->irq has been set. Reported-by: Michael Buesch Signed-off-by: Thomas Gleixner Tested-by: Michael Buesch --- kernel/irq/manage.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index d222515..0ec9ed8 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -607,7 +607,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) */ get_task_struct(t); new->thread = t; - wake_up_process(t); } /* @@ -690,6 +689,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) (int)(new->flags & IRQF_TRIGGER_MASK)); } + new->irq = irq; *old_ptr = new; /* Reset broken irq detection when installing new handler */ @@ -707,7 +707,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) spin_unlock_irqrestore(&desc->lock, flags); - new->irq = irq; + /* + * Strictly no need to wake it up, but hung_task complains + * when no hard interrupt wakes the thread up. + */ + if (new->thread) + wake_up_process(new->thread); + register_irq_proc(irq, desc); new->dir = NULL; register_handler_proc(irq, new); -- cgit v1.1 From 0753ba01e126020bf0f8150934903b48935b697d Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Tue, 18 Aug 2009 14:11:10 -0700 Subject: mm: revert "oom: move oom_adj value" The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to the mm_struct. It was a very good first step for sanitize OOM. However Paul Menage reported the commit makes regression to his job scheduler. Current OOM logic can kill OOM_DISABLED process. Why? His program has the code of similar to the following. ... set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */ ... if (vfork() == 0) { set_oom_adj(0); /* Invoked child can be killed */ execve("foo-bar-cmd"); } .... vfork() parent and child are shared the same mm_struct. then above set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also change oom_adj for vfork() parent. Then, vfork() parent (job scheduler) lost OOM immune and it was killed. Actually, fork-setting-exec idiom is very frequently used in userland program. We must not break this assumption. Then, this patch revert commit 2ff05b2b and related commit. Reverted commit list --------------------- - commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct) - commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE) - commit 8123681022 (oom: only oom kill exiting tasks with attached memory) - commit 933b787b57 (mm: copy over oom_adj value at fork time) Signed-off-by: KOSAKI Motohiro Cc: Paul Menage Cc: David Rientjes Cc: KAMEZAWA Hiroyuki Cc: Rik van Riel Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Nick Piggin Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 021e113..144326b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -426,7 +426,6 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) init_rwsem(&mm->mmap_sem); INIT_LIST_HEAD(&mm->mmlist); mm->flags = (current->mm) ? current->mm->flags : default_dump_filter; - mm->oom_adj = (current->mm) ? current->mm->oom_adj : 0; mm->core_state = NULL; mm->nr_ptes = 0; set_mm_counter(mm, file_rss, 0); -- cgit v1.1 From eda1e328556565e211b7450250e40d6de751563a Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 11 Aug 2009 17:29:04 +0200 Subject: tracing: handle broken names in ftrace filter If one filter item (for set_ftrace_filter and set_ftrace_notrace) is being setup by more than 1 consecutive writes (FTRACE_ITER_CONT flag), it won't be handled corretly. I used following program to test/verify: [snip] #include #include #include #include #include int main(int argc, char **argv) { int fd, i; char *file = argv[1]; if (-1 == (fd = open(file, O_WRONLY))) { perror("open failed"); return -1; } for(i = 0; i < (argc - 2); i++) { int len = strlen(argv[2+i]); int cnt, off = 0; while(len) { cnt = write(fd, argv[2+i] + off, len); len -= cnt; off += cnt; } } close(fd); return 0; } [snip] before change: sh-4.0# echo > ./set_ftrace_filter sh-4.0# /test ./set_ftrace_filter "sys" "_open " sh-4.0# cat ./set_ftrace_filter #### all functions enabled #### sh-4.0# after change: sh-4.0# echo > ./set_ftrace_notrace sh-4.0# test ./set_ftrace_notrace "sys" "_open " sh-4.0# cat ./set_ftrace_notrace sys_open sh-4.0# Signed-off-by: Jiri Olsa LKML-Reference: <20090811152904.GA26065@jolsa.lab.eng.brq.redhat.com> Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1e1d23c..25edd5c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2278,7 +2278,11 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, read++; cnt--; - if (!(iter->flags & ~FTRACE_ITER_CONT)) { + /* + * If the parser haven't finished with the last write, + * continue reading the user input without skipping spaces. + */ + if (!(iter->flags & FTRACE_ITER_CONT)) { /* skip white space */ while (cnt && isspace(ch)) { ret = get_user(ch, ubuf++); @@ -2288,8 +2292,9 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, cnt--; } + /* only spaces were written */ if (isspace(ch)) { - file->f_pos += read; + *ppos += read; ret = read; goto out; } @@ -2319,12 +2324,12 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, if (ret) goto out; iter->buffer_idx = 0; - } else + } else { iter->flags |= FTRACE_ITER_CONT; + iter->buffer[iter->buffer_idx++] = ch; + } - - file->f_pos += read; - + *ppos += read; ret = read; out: mutex_unlock(&ftrace_regex_lock); -- cgit v1.1 From f833bab87fca5c3ce13778421b1365845843b976 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 17 Aug 2009 14:34:59 -0700 Subject: clockevent: Prevent dead lock on clockevents_lock Currently clockevents_notify() is called with interrupts enabled at some places and interrupts disabled at some other places. This results in a deadlock in this scenario. cpu A holds clockevents_lock in clockevents_notify() with irqs enabled cpu B waits for clockevents_lock in clockevents_notify() with irqs disabled cpu C doing set_mtrr() which will try to rendezvous of all the cpus. This will result in C and A come to the rendezvous point and waiting for B. B is stuck forever waiting for the spinlock and thus not reaching the rendezvous point. Fix the clockevents code so that clockevents_lock is taken with interrupts disabled and thus avoid the above deadlock. Also call lapic_timer_propagate_broadcast() on the destination cpu so that we avoid calling smp_call_function() in the clockevents notifier chain. This issue left us wondering if we need to change the MTRR rendezvous logic to use stop machine logic (instead of smp_call_function) or add a check in spinlock debug code to see if there are other spinlocks which gets taken under both interrupts enabled/disabled conditions. Signed-off-by: Suresh Siddha Signed-off-by: Venkatesh Pallipadi Cc: "Pallipadi Venkatesh" Cc: "Brown Len" LKML-Reference: <1250544899.2709.210.camel@sbs-t61.sc.intel.com> Signed-off-by: Thomas Gleixner --- kernel/time/clockevents.c | 16 ++++++++++------ kernel/time/tick-broadcast.c | 7 +++---- 2 files changed, 13 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index a6dcd67..620b58a 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -137,11 +137,12 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, */ int clockevents_register_notifier(struct notifier_block *nb) { + unsigned long flags; int ret; - spin_lock(&clockevents_lock); + spin_lock_irqsave(&clockevents_lock, flags); ret = raw_notifier_chain_register(&clockevents_chain, nb); - spin_unlock(&clockevents_lock); + spin_unlock_irqrestore(&clockevents_lock, flags); return ret; } @@ -178,16 +179,18 @@ static void clockevents_notify_released(void) */ void clockevents_register_device(struct clock_event_device *dev) { + unsigned long flags; + BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); BUG_ON(!dev->cpumask); - spin_lock(&clockevents_lock); + spin_lock_irqsave(&clockevents_lock, flags); list_add(&dev->list, &clockevent_devices); clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev); clockevents_notify_released(); - spin_unlock(&clockevents_lock); + spin_unlock_irqrestore(&clockevents_lock, flags); } EXPORT_SYMBOL_GPL(clockevents_register_device); @@ -235,8 +238,9 @@ void clockevents_exchange_device(struct clock_event_device *old, void clockevents_notify(unsigned long reason, void *arg) { struct list_head *node, *tmp; + unsigned long flags; - spin_lock(&clockevents_lock); + spin_lock_irqsave(&clockevents_lock, flags); clockevents_do_notify(reason, arg); switch (reason) { @@ -251,7 +255,7 @@ void clockevents_notify(unsigned long reason, void *arg) default: break; } - spin_unlock(&clockevents_lock); + spin_unlock_irqrestore(&clockevents_lock, flags); } EXPORT_SYMBOL_GPL(clockevents_notify); #endif diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 877dbed..c2ec250 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -205,11 +205,11 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev) * Powerstate information: The system enters/leaves a state, where * affected devices might stop */ -static void tick_do_broadcast_on_off(void *why) +static void tick_do_broadcast_on_off(unsigned long *reason) { struct clock_event_device *bc, *dev; struct tick_device *td; - unsigned long flags, *reason = why; + unsigned long flags; int cpu, bc_stopped; spin_lock_irqsave(&tick_broadcast_lock, flags); @@ -276,8 +276,7 @@ void tick_broadcast_on_off(unsigned long reason, int *oncpu) printk(KERN_ERR "tick-broadcast: ignoring broadcast for " "offline CPU #%d\n", *oncpu); else - smp_call_function_single(*oncpu, tick_do_broadcast_on_off, - &reason, 1); + tick_do_broadcast_on_off(&reason); } /* -- cgit v1.1 From 4464fcaa9cbfc9c551956b48af203e2f775ca892 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 Aug 2009 17:19:36 +0200 Subject: perf_counter: Fix typo in read() output generation When you iterate a list, using the iterator is useful. Before: ID: 5 ID: 5 ID: 5 ID: 5 EVNT: 0x40088b scale: nan ID: 5 CNT: 1006252 ID: 6 CNT: 1011090 ID: 7 CNT: 1011196 ID: 8 CNT: 1011095 EVNT: 0x40088c scale: 1.000000 ID: 5 CNT: 2003065 ID: 6 CNT: 2011671 ID: 7 CNT: 2012620 ID: 8 CNT: 2013479 EVNT: 0x40088c scale: 1.000000 ID: 5 CNT: 3002390 ID: 6 CNT: 3015996 ID: 7 CNT: 3018019 ID: 8 CNT: 3020006 EVNT: 0x40088b scale: 1.000000 ID: 5 CNT: 4002406 ID: 6 CNT: 4021120 ID: 7 CNT: 4024241 ID: 8 CNT: 4027059 After: ID: 1 ID: 2 ID: 3 ID: 4 EVNT: 0x400889 scale: nan ID: 1 CNT: 1005270 ID: 2 CNT: 1009833 ID: 3 CNT: 1010065 ID: 4 CNT: 1010088 EVNT: 0x400898 scale: nan ID: 1 CNT: 2001531 ID: 2 CNT: 2022309 ID: 3 CNT: 2022470 ID: 4 CNT: 2022627 EVNT: 0x400888 scale: 0.489467 ID: 1 CNT: 3001261 ID: 2 CNT: 3027088 ID: 3 CNT: 3027941 ID: 4 CNT: 3028762 Reported-by: stephane eranian Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey J Ashford Cc: perfmon2-devel LKML-Reference: <1250867976.7538.73.camel@twins> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 36f65e2..f274e19 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1791,7 +1791,7 @@ static int perf_counter_read_group(struct perf_counter *counter, size += err; list_for_each_entry(sub, &leader->sibling_list, list_entry) { - err = perf_counter_read_entry(counter, read_format, + err = perf_counter_read_entry(sub, read_format, buf + size); if (err < 0) return err; -- cgit v1.1 From cd0980fc8add25e8ab12fcf1051c0f20cbc7c0c0 Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Tue, 25 Aug 2009 14:50:27 +0200 Subject: tracing: Check invalid syscall nr while tracing syscalls Most arch syscall_get_nr() implementations returns -1 if the syscall number is not valid. Accessing the bit field without a check might result in a kernel oops (at least I saw it on s390 for ftrace selftest). Before this change, this problem did not occur, because the invalid syscall number (-1) caused syscall_nr_to_meta() to return NULL. There are at least two scenarios where syscall_get_nr() can return -1: 1. For example, ptrace stores an invalid syscall number, and thus, tracing code resets it. (see do_syscall_trace_enter in arch/s390/kernel/ptrace.c) 2. The syscall_regfunc() (kernel/tracepoint.c) sets the TIF_SYSCALL_FTRACE (now: TIF_SYSCALL_TRACEPOINT) flag for all threads which include kernel threads. However, the ftrace selftest triggers a kernel oops when testing syscall trace points: - The kernel thread is started as ususal (do_fork()), - tracing code sets TIF_SYSCALL_FTRACE, - the ret_from_fork() function is triggered and starts ftrace_syscall_exit() with an invalid syscall number. To avoid these scenarios, I suggest to check the syscall_nr. For instance, the ftrace selftest fails for s390 (with config option CONFIG_FTRACE_SYSCALLS set) and produces the following kernel oops. Unable to handle kernel pointer dereference at virtual kernel address 2000000000 Oops: 0038 [#1] PREEMPT SMP Modules linked in: CPU: 0 Not tainted 2.6.31-rc6-next-20090819-dirty #18 Process kthreadd (pid: 818, task: 000000003ea207e8, ksp: 000000003e813eb8) Krnl PSW : 0704100180000000 00000000000ea54c (ftrace_syscall_exit+0x58/0xdc) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0 EA:3 Krnl GPRS: 0000000000000000 00000000000e0000 ffffffffffffffff 20000000008c2650 0000000000000007 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 ffffffffffffffff 000000003e813d78 000000003e813f58 0000000000505ba8 000000003e813e18 000000003e813d78 Krnl Code: 00000000000ea540: e330d0000008 ag %r3,0(%r13) 00000000000ea546: a7480007 lhi %r4,7 00000000000ea54a: 1442 nr %r4,%r2 >00000000000ea54c: e31030000090 llgc %r1,0(%r3) 00000000000ea552: 5410d008 n %r1,8(%r13) 00000000000ea556: 8a104000 sra %r1,0(%r4) 00000000000ea55a: 5410d00c n %r1,12(%r13) 00000000000ea55e: 1211 ltr %r1,%r1 Call Trace: ([<0000000000000000>] 0x0) [<000000000001fa22>] do_syscall_trace_exit+0x132/0x18c [<000000000002d0c4>] sysc_return+0x0/0x8 [<000000000001c738>] kernel_thread_starter+0x0/0xc Last Breaking-Event-Address: [<00000000000ea51e>] ftrace_syscall_exit+0x2a/0xdc Signed-off-by: Hendrik Brueckner Acked-by: Heiko Carstens Cc: Jason Baron Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Lai Jiangshan Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Mathieu Desnoyers Cc: Jiaying Zhang Cc: Martin Bligh Cc: Li Zefan Cc: Martin Schwidefsky Cc: Paul Mundt LKML-Reference: <20090825125027.GE4639@cetus.boeblingen.de.ibm.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace_syscalls.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 85291c4..cb7f600 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -227,6 +227,8 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id) int syscall_nr; syscall_nr = syscall_get_nr(current, regs); + if (syscall_nr < 0) + return; if (!test_bit(syscall_nr, enabled_enter_syscalls)) return; @@ -257,6 +259,8 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret) int syscall_nr; syscall_nr = syscall_get_nr(current, regs); + if (syscall_nr < 0) + return; if (!test_bit(syscall_nr, enabled_exit_syscalls)) return; -- cgit v1.1 From cc3b13c11c567c69a6356be98d0c03ff11541d5c Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Tue, 25 Aug 2009 18:02:37 +0200 Subject: tracing: Don't trace kernel thread syscalls Kernel threads don't call syscalls using the sysenter/sysexit path. Instead they directly call the sys_* or do_* functions that implement the syscalls inside the kernel. The current syscall tracepoints only bind the sysenter/sysexit path, then it has no effect to trace the kernel thread calls to syscalls in that path. Setting the TIF_SYSCALL_TRACEPOINT flag is then useless for these. Actually there is only one case when a kernel thread can reach the usual syscall exit tracing path: when we create a kernel thread, the child comes to ret_from_fork and is the fork() return is then traced. But this information alone is useless, then we don't want to set the TIF flags for these threads. Kernel threads have task_struct->mm set to NULL. (Thanks to Heiko for that hint ;-) The idea is then to check the mm field in syscall_regfunc() and set the flag accordingly. Signed-off-by: Hendrik Brueckner Cc: Jason Baron Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Lai Jiangshan Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Mathieu Desnoyers Cc: Jiaying Zhang Cc: Martin Bligh Cc: Li Zefan Cc: Martin Schwidefsky Cc: Paul Mundt Cc: Heiko Carstens Cc: Hendrik Brueckner LKML-Reference: <20090825160237.GG4639@cetus.boeblingen.de.ibm.com> Signed-off-by: Frederic Weisbecker --- kernel/tracepoint.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 1a6a453..9489a0a 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -597,7 +597,9 @@ void syscall_regfunc(void) if (!sys_tracepoint_refcount) { read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, t) { - set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); + /* Skip kernel threads. */ + if (t->mm) + set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); } while_each_thread(g, t); read_unlock_irqrestore(&tasklist_lock, flags); } -- cgit v1.1 From 57421dbbdc932d65f0e6a41ebb027a2bfe3d0669 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Mon, 24 Aug 2009 17:40:22 -0400 Subject: tracing: Convert event tracing code to use NR_syscalls Convert the syscalls event tracing code to use NR_syscalls, instead of FTRACE_SYSCALL_MAX. NR_syscalls is standard accross most arches, and reduces code confusion/complexity. Signed-off-by: Jason Baron Cc: Paul Mundt Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Lai Jiangshan Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Mathieu Desnoyers Cc: Jiaying Zhang Cc: Martin Bligh Cc: Li Zefan Cc: Josh Stone Cc: Thomas Gleixner Cc: H. Peter Anwin Cc: Hendrik Brueckner Cc: Heiko Carstens LKML-Reference: <9b4f1a84ecae57cc6599412772efa36f0d2b815b.1251146513.git.jbaron@redhat.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace_syscalls.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index cb7f600..4f5fae6 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -11,8 +11,8 @@ static DEFINE_MUTEX(syscall_trace_lock); static int sys_refcount_enter; static int sys_refcount_exit; -static DECLARE_BITMAP(enabled_enter_syscalls, FTRACE_SYSCALL_MAX); -static DECLARE_BITMAP(enabled_exit_syscalls, FTRACE_SYSCALL_MAX); +static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls); +static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls); enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags) @@ -289,7 +289,7 @@ int reg_event_syscall_enter(void *ptr) name = (char *)ptr; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return -ENOSYS; mutex_lock(&syscall_trace_lock); if (!sys_refcount_enter) @@ -312,7 +312,7 @@ void unreg_event_syscall_enter(void *ptr) name = (char *)ptr; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return; mutex_lock(&syscall_trace_lock); sys_refcount_enter--; @@ -330,7 +330,7 @@ int reg_event_syscall_exit(void *ptr) name = (char *)ptr; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return -ENOSYS; mutex_lock(&syscall_trace_lock); if (!sys_refcount_exit) @@ -353,7 +353,7 @@ void unreg_event_syscall_exit(void *ptr) name = (char *)ptr; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return; mutex_lock(&syscall_trace_lock); sys_refcount_exit--; @@ -373,8 +373,8 @@ struct trace_event event_syscall_exit = { #ifdef CONFIG_EVENT_PROFILE -static DECLARE_BITMAP(enabled_prof_enter_syscalls, FTRACE_SYSCALL_MAX); -static DECLARE_BITMAP(enabled_prof_exit_syscalls, FTRACE_SYSCALL_MAX); +static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls); +static DECLARE_BITMAP(enabled_prof_exit_syscalls, NR_syscalls); static int sys_prof_refcount_enter; static int sys_prof_refcount_exit; @@ -420,7 +420,7 @@ int reg_prof_syscall_enter(char *name) int num; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return -ENOSYS; mutex_lock(&syscall_trace_lock); @@ -442,7 +442,7 @@ void unreg_prof_syscall_enter(char *name) int num; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return; mutex_lock(&syscall_trace_lock); @@ -481,7 +481,7 @@ int reg_prof_syscall_exit(char *name) int num; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return -ENOSYS; mutex_lock(&syscall_trace_lock); @@ -503,7 +503,7 @@ void unreg_prof_syscall_exit(char *name) int num; num = syscall_name_to_nr(name); - if (num < 0 || num >= FTRACE_SYSCALL_MAX) + if (num < 0 || num >= NR_syscalls) return; mutex_lock(&syscall_trace_lock); -- cgit v1.1 From 4ab6c08336535f8c8e42cf45d7adeda882eff06e Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 26 Aug 2009 14:29:24 -0700 Subject: clone(): fix race between copy_process() and de_thread() Spotted by Hiroshi Shimamoto who also provided the test-case below. copy_process() uses signal->count as a reference counter, but it is not. This test case #include #include #include #include #include #include void *null_thread(void *p) { for (;;) sleep(1); return NULL; } void *exec_thread(void *p) { execl("/bin/true", "/bin/true", NULL); return null_thread(p); } int main(int argc, char **argv) { for (;;) { pid_t pid; int ret, status; pid = fork(); if (pid < 0) break; if (!pid) { pthread_t tid; pthread_create(&tid, NULL, exec_thread, NULL); for (;;) pthread_create(&tid, NULL, null_thread, NULL); } do { ret = waitpid(pid, &status, 0); } while (ret == -1 && errno == EINTR); } return 0; } quickly creates an unkillable task. If copy_process(CLONE_THREAD) races with de_thread() copy_signal()->atomic(signal->count) breaks the signal->notify_count logic, and the execing thread can hang forever in kernel space. Change copy_process() to increment count/live only when we know for sure we can't fail. In this case the forked thread will take care of its reference to signal correctly. If copy_process() fails, check CLONE_THREAD flag. If it it set - do nothing, the counters were not changed and current belongs to the same thread group. If it is not set, ->signal must be released in any case (and ->count must be == 1), the forked child is the only thread in the thread group. We need more cleanups here, in particular signal->count should not be used by de_thread/__exit_signal at all. This patch only fixes the bug. Reported-by: Hiroshi Shimamoto Tested-by: Hiroshi Shimamoto Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Cc: KAMEZAWA Hiroyuki Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 144326b..e6c04d4 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -815,11 +815,8 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) { struct signal_struct *sig; - if (clone_flags & CLONE_THREAD) { - atomic_inc(¤t->signal->count); - atomic_inc(¤t->signal->live); + if (clone_flags & CLONE_THREAD) return 0; - } sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); tsk->signal = sig; @@ -877,16 +874,6 @@ void __cleanup_signal(struct signal_struct *sig) kmem_cache_free(signal_cachep, sig); } -static void cleanup_signal(struct task_struct *tsk) -{ - struct signal_struct *sig = tsk->signal; - - atomic_dec(&sig->live); - - if (atomic_dec_and_test(&sig->count)) - __cleanup_signal(sig); -} - static void copy_flags(unsigned long clone_flags, struct task_struct *p) { unsigned long new_flags = p->flags; @@ -1239,6 +1226,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, } if (clone_flags & CLONE_THREAD) { + atomic_inc(¤t->signal->count); + atomic_inc(¤t->signal->live); p->group_leader = current->group_leader; list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); } @@ -1282,7 +1271,8 @@ bad_fork_cleanup_mm: if (p->mm) mmput(p->mm); bad_fork_cleanup_signal: - cleanup_signal(p); + if (!(clone_flags & CLONE_THREAD)) + __cleanup_signal(p->signal); bad_fork_cleanup_sighand: __cleanup_sighand(p->sighand); bad_fork_cleanup_fs: -- cgit v1.1 From 7d1d16e416e61aeef8655d542f8e4a4fc6e808e4 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 26 Aug 2009 22:02:54 +0930 Subject: module: fix BUG_ON() for powerpc (and other function descriptor archs) The rarely-used symbol_put_addr() needs to use dereference_function_descriptor on powerpc. Reported-by: Paul Mackerras Signed-off-by: Rusty Russell --- kernel/module.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index fd141140..07c80e6 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -909,16 +909,18 @@ void __symbol_put(const char *symbol) } EXPORT_SYMBOL(__symbol_put); +/* Note this assumes addr is a function, which it currently always is. */ void symbol_put_addr(void *addr) { struct module *modaddr; + unsigned long a = (unsigned long)dereference_function_descriptor(addr); - if (core_kernel_text((unsigned long)addr)) + if (core_kernel_text(a)) return; /* module_text_address is safe here: we're supposed to have reference * to module from symbol_get, so it can't go away. */ - modaddr = __module_text_address((unsigned long)addr); + modaddr = __module_text_address(a); BUG_ON(!modaddr); module_put(modaddr); } -- cgit v1.1 From 1b364bf438cf337a3818aee77d68c0713f3e1fc4 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Wed, 26 Aug 2009 22:04:12 +0930 Subject: module: workaround duplicate section names The root cause is a duplicate section name (.text); is this legal? [ Amerigo Wang: "AFAIK, yes." ] However, there's a problem with commit 6d76013381ed28979cd122eb4b249a88b5e384fa in that if you fail to allocate a mod->sect_attrs (in this case it's null because of the duplication), it still gets used without checking in add_notes_attrs() This should fix it [ This patch leaves other problems, particularly the sections directory, but recent parisc toolchains seem to produce these modules and this prevents a crash and is a minimal change -- RR ] Signed-off-by: James Bottomley Signed-off-by: Rusty Russell Tested-by: Helge Deller Signed-off-by: Linus Torvalds --- kernel/module.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 07c80e6..eccb561 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2355,7 +2355,8 @@ static noinline struct module *load_module(void __user *umod, if (err < 0) goto unlink; add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs); - add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs); + if (mod->sect_attrs) + add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs); /* Get rid of temporary copy */ vfree(hdr); -- cgit v1.1 From c0729be99cb2b9d9749256254f1c40a801835896 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 26 Aug 2009 22:23:52 -0400 Subject: tracing: remove legacy select of MARKERS by context switch tracing The context switch tracer was made before tracepoints were mature, and the original version used markers. This is no longer true and this patch removes the select. Reported-by: Thomas Gleixner Signed-off-by: Steven Rostedt --- kernel/trace/Kconfig | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 06be85a..163fbfc 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -60,7 +60,6 @@ config EVENT_TRACING bool config CONTEXT_SWITCH_TRACER - select MARKERS bool # All tracer options should select GENERIC_TRACER. For those options that are -- cgit v1.1 From 5d4a9dba2d7fbab69f00dedd430d1788834a055a Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 27 Aug 2009 16:52:21 -0400 Subject: tracing: only show tracing_max_latency when latency tracer configured The tracing_max_latency file should only be present when one of the latency tracers ({preempt|irqs}off, wakeup*) are enabled. This patch also removes tracing_thresh when latency tracers are not enabled, as well as compiles out code that is only used for latency tracers. Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 92 ++++++++++++++++++++++++++++------------------------ kernel/trace/trace.h | 2 ++ 2 files changed, 52 insertions(+), 42 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 63dbc7f..0f08816 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -43,9 +43,6 @@ #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE) -unsigned long __read_mostly tracing_max_latency; -unsigned long __read_mostly tracing_thresh; - /* * On boot up, the ring buffer is set to the minimum size, so that * we do not waste memory on systems that are not using tracing. @@ -338,45 +335,6 @@ static struct { int trace_clock_id; -/* - * ftrace_max_lock is used to protect the swapping of buffers - * when taking a max snapshot. The buffers themselves are - * protected by per_cpu spinlocks. But the action of the swap - * needs its own lock. - * - * This is defined as a raw_spinlock_t in order to help - * with performance when lockdep debugging is enabled. - */ -static raw_spinlock_t ftrace_max_lock = - (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; - -/* - * Copy the new maximum trace into the separate maximum-trace - * structure. (this way the maximum trace is permanently saved, - * for later retrieval via /sys/kernel/debug/tracing/latency_trace) - */ -static void -__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) -{ - struct trace_array_cpu *data = tr->data[cpu]; - - max_tr.cpu = cpu; - max_tr.time_start = data->preempt_timestamp; - - data = max_tr.data[cpu]; - data->saved_latency = tracing_max_latency; - - memcpy(data->comm, tsk->comm, TASK_COMM_LEN); - data->pid = tsk->pid; - data->uid = task_uid(tsk); - data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; - data->policy = tsk->policy; - data->rt_priority = tsk->rt_priority; - - /* record this tasks comm */ - tracing_record_cmdline(tsk); -} - ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) { int len; @@ -420,6 +378,53 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) return cnt; } +/* + * ftrace_max_lock is used to protect the swapping of buffers + * when taking a max snapshot. The buffers themselves are + * protected by per_cpu spinlocks. But the action of the swap + * needs its own lock. + * + * This is defined as a raw_spinlock_t in order to help + * with performance when lockdep debugging is enabled. + * + * It is also used in other places outside the update_max_tr + * so it needs to be defined outside of the + * CONFIG_TRACER_MAX_TRACE. + */ +static raw_spinlock_t ftrace_max_lock = + (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; + +#ifdef CONFIG_TRACER_MAX_TRACE +unsigned long __read_mostly tracing_max_latency; +unsigned long __read_mostly tracing_thresh; + +/* + * Copy the new maximum trace into the separate maximum-trace + * structure. (this way the maximum trace is permanently saved, + * for later retrieval via /sys/kernel/debug/tracing/latency_trace) + */ +static void +__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) +{ + struct trace_array_cpu *data = tr->data[cpu]; + + max_tr.cpu = cpu; + max_tr.time_start = data->preempt_timestamp; + + data = max_tr.data[cpu]; + data->saved_latency = tracing_max_latency; + + memcpy(data->comm, tsk->comm, TASK_COMM_LEN); + data->pid = tsk->pid; + data->uid = task_uid(tsk); + data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; + data->policy = tsk->policy; + data->rt_priority = tsk->rt_priority; + + /* record this tasks comm */ + tracing_record_cmdline(tsk); +} + /** * update_max_tr - snapshot all trace buffers from global_trace to max_tr * @tr: tracer @@ -476,6 +481,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) __update_max_tr(tr, tsk, cpu); __raw_spin_unlock(&ftrace_max_lock); } +#endif /* CONFIG_TRACER_MAX_TRACE */ /** * register_tracer - register a tracer with the ftrace system. @@ -3952,11 +3958,13 @@ static __init int tracer_init_debugfs(void) trace_create_file("current_tracer", 0644, d_tracer, &global_trace, &set_tracer_fops); +#ifdef CONFIG_TRACER_MAX_TRACE trace_create_file("tracing_max_latency", 0644, d_tracer, &tracing_max_latency, &tracing_max_lat_fops); trace_create_file("tracing_thresh", 0644, d_tracer, &tracing_thresh, &tracing_max_lat_fops); +#endif trace_create_file("README", 0444, d_tracer, NULL, &tracing_readme_fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 654fd65..e2c06b2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -473,12 +473,14 @@ void unregister_tracer(struct tracer *type); extern unsigned long nsecs_to_usecs(unsigned long nsecs); +#ifdef CONFIG_TRACER_MAX_TRACE extern unsigned long tracing_max_latency; extern unsigned long tracing_thresh; void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu); void update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu); +#endif /* CONFIG_TRACER_MAX_TRACE */ #ifdef CONFIG_STACKTRACE void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, -- cgit v1.1 From 6bb56347f5162d1a7cb1dc461023360781ecd4c0 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 28 Aug 2009 13:44:53 +0200 Subject: perf_counters: Increase paranoia level Per-cpu counters are an ASLR information leak as they show the execution other tasks do. Increase the paranoia level to 1, which disallows per-cpu counters. (they still allow counting/profiling of own tasks - and admin can profile everything.) Acked-by: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index f274e19..7d4bb83 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -50,7 +50,7 @@ static atomic_t nr_task_counters __read_mostly; * 1 - disallow cpu counters to unpriv * 2 - disallow kernel profiling to unpriv */ -int sysctl_perf_counter_paranoid __read_mostly; +int sysctl_perf_counter_paranoid __read_mostly = 1; static inline bool perf_paranoid_cpu(void) { -- cgit v1.1 From ea6bff368548d79529421a9dc0710fc5330eb504 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 28 Aug 2009 10:44:56 +0200 Subject: modules: Fix build error in the !CONFIG_KALLSYMS case MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit > James Bottomley (1): > module: workaround duplicate section names -tip testing found that this patch breaks the build on x86 if CONFIG_KALLSYMS is disabled: kernel/module.c: In function ‘load_module’: kernel/module.c:2367: error: ‘struct module’ has no member named ‘sect_attrs’ distcc[8269] ERROR: compile kernel/module.c on ph/32 failed make[1]: *** [kernel/module.o] Error 1 make: *** [kernel] Error 2 make: *** Waiting for unfinished jobs.... Commit 1b364bf misses the fact that section attributes are only built and dealt with if kallsyms is enabled. The patch below fixes this. ( note, technically speaking this should depend on CONFIG_SYSFS as well but this patch is correct too and keeps the #ifdef less intrusive - in the KALLSYMS && !SYSFS case the code is a NOP. ) Signed-off-by: Ingo Molnar [ Replaced patch with a slightly cleaner variation by James Bottomley ] Signed-off-by: Linus Torvalds --- kernel/module.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index eccb561..2d53718 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1274,6 +1274,10 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, struct module_notes_attrs *notes_attrs; struct bin_attribute *nattr; + /* failed to create section attributes, so can't create notes */ + if (!mod->sect_attrs) + return; + /* Count notes sections and allocate structures. */ notes = 0; for (i = 0; i < nsect; i++) @@ -2355,8 +2359,7 @@ static noinline struct module *load_module(void __user *umod, if (err < 0) goto unlink; add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs); - if (mod->sect_attrs) - add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs); + add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs); /* Get rid of temporary copy */ vfree(hdr); -- cgit v1.1 From eced1dfcfcf6b0a35e925d73916a9d8e36ab5457 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 28 Aug 2009 17:10:47 +0200 Subject: perf_counter: Fix /0 bug in swcounters We have a race in the swcounter stuff where we can start counting a counter that has never been enabled, this leads to a /0 situation. The below avoids the /0 but doesn't close the race, this would need a new counter state. The race is due to perf_swcounter_is_counting() which cannot discern between disabled due to scheduled out, and disabled for any other reason. Such a crash has been seen by Ingo: [ 967.092372] divide error: 0000 [#1] SMP [ 967.096499] last sysfs file: /sys/devices/system/cpu/cpu15/cache/index2/shared_cpu_map [ 967.104846] CPU 5 [ 967.106965] Modules linked in: [ 967.110169] Pid: 3351, comm: hackbench Not tainted 2.6.31-rc8-tip-01158-gd940a54-dirty #1568 X8DTN [ 967.119456] RIP: 0010:[] [] perf_swcounter_ctx_event+0x127/0x1af [ 967.129137] RSP: 0018:ffff8801a95abd70 EFLAGS: 00010046 [ 967.134699] RAX: 0000000000000002 RBX: ffff8801bd645c00 RCX: 0000000000000002 [ 967.142162] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801bd645d40 [ 967.149584] RBP: ffff8801a95abdb0 R08: 0000000000000001 R09: ffff8801a95abe00 [ 967.157042] R10: 0000000000000037 R11: ffff8801aa1245f8 R12: ffff8801a95abe00 [ 967.164481] R13: ffff8801a95abe00 R14: ffff8801aa1c0e78 R15: 0000000000000001 [ 967.171953] FS: 0000000000000000(0000) GS:ffffc90000a00000(0063) knlGS:00000000f7f486c0 [ 967.180406] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 967.186374] CR2: 000000004822c0ac CR3: 00000001b19a2000 CR4: 00000000000006e0 [ 967.193770] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 967.201224] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 967.208692] Process hackbench (pid: 3351, threadinfo ffff8801a95aa000, task ffff8801a96b0000) [ 967.217607] Stack: [ 967.219711] 0000000000000000 0000000000000037 0000000200000001 ffffc90000a1107c [ 967.227296] <0> ffff8801a95abe00 0000000000000001 0000000000000001 0000000000000037 [ 967.235333] <0> ffff8801a95abdf0 ffffffff810c0c20 0000000200a14f30 ffff8801a95abe40 [ 967.243532] Call Trace: [ 967.246103] [] do_perf_swcounter_event+0xde/0xec [ 967.252635] [] perf_tpcounter_event+0x79/0x7b [ 967.258957] [] ftrace_profile_sched_switch+0xc0/0xcb [ 967.265791] [] schedule+0x429/0x4c4 [ 967.271156] [] int_careful+0xd/0x14 Reported-by: Ingo Molnar Signed-off-by: Peter Zijlstra Cc: Paul Mackerras LKML-Reference: <1251472247.17617.74.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 7d4bb83..d7cbc57 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -4066,6 +4066,7 @@ perf_counter_alloc(struct perf_counter_attr *attr, hwc->sample_period = attr->sample_period; if (attr->freq && attr->sample_freq) hwc->sample_period = 1; + hwc->last_period = hwc->sample_period; atomic64_set(&hwc->period_left, hwc->sample_period); -- cgit v1.1 From 8e254c1d183f0225ad21f9049641529e56cce4da Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 31 Aug 2009 16:49:41 +0800 Subject: tracing/filters: Defer pred allocation init_preds() allocates about 5392 bytes of memory (on x86_32) for a TRACE_EVENT. With my config, at system boot total memory occupied is: 5392 * (642 + 15) == 3459KB 642 == cat available_events | wc -l 15 == number of dirs in events/ftrace That's quite a lot, so we'd better defer memory allocation util it's needed, that's when filter is used. Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Tom Zanussi Cc: Masami Hiramatsu LKML-Reference: <4A9B8EA5.6020700@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace_events_filter.c | 50 +++++++++++++++++++++++++++++++------- kernel/trace/trace_export.c | 1 - 2 files changed, 41 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 9f03082..c6b2edf 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -309,7 +309,7 @@ void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s) struct event_filter *filter = call->filter; mutex_lock(&event_mutex); - if (filter->filter_string) + if (filter && filter->filter_string) trace_seq_printf(s, "%s\n", filter->filter_string); else trace_seq_printf(s, "none\n"); @@ -322,7 +322,7 @@ void print_subsystem_event_filter(struct event_subsystem *system, struct event_filter *filter = system->filter; mutex_lock(&event_mutex); - if (filter->filter_string) + if (filter && filter->filter_string) trace_seq_printf(s, "%s\n", filter->filter_string); else trace_seq_printf(s, "none\n"); @@ -390,6 +390,9 @@ void destroy_preds(struct ftrace_event_call *call) struct event_filter *filter = call->filter; int i; + if (!filter) + return; + for (i = 0; i < MAX_FILTER_PRED; i++) { if (filter->preds[i]) filter_free_pred(filter->preds[i]); @@ -400,7 +403,7 @@ void destroy_preds(struct ftrace_event_call *call) call->filter = NULL; } -int init_preds(struct ftrace_event_call *call) +static int init_preds(struct ftrace_event_call *call) { struct event_filter *filter; struct filter_pred *pred; @@ -410,7 +413,6 @@ int init_preds(struct ftrace_event_call *call) if (!call->filter) return -ENOMEM; - call->filter_active = 0; filter->n_preds = 0; filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL); @@ -432,7 +434,28 @@ oom: return -ENOMEM; } -EXPORT_SYMBOL_GPL(init_preds); + +static int init_subsystem_preds(struct event_subsystem *system) +{ + struct ftrace_event_call *call; + int err; + + list_for_each_entry(call, &ftrace_events, list) { + if (!call->define_fields) + continue; + + if (strcmp(call->system, system->name) != 0) + continue; + + if (!call->filter) { + err = init_preds(call); + if (err) + return err; + } + } + + return 0; +} enum { FILTER_DISABLE_ALL, @@ -449,6 +472,9 @@ static void filter_free_subsystem_preds(struct event_subsystem *system, if (!call->define_fields) continue; + if (strcmp(call->system, system->name) != 0) + continue; + if (flag == FILTER_INIT_NO_RESET) { call->filter->no_reset = false; continue; @@ -457,10 +483,8 @@ static void filter_free_subsystem_preds(struct event_subsystem *system, if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset) continue; - if (!strcmp(call->system, system->name)) { - filter_disable_preds(call); - remove_filter_string(call->filter); - } + filter_disable_preds(call); + remove_filter_string(call->filter); } } @@ -1094,6 +1118,10 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) mutex_lock(&event_mutex); + err = init_preds(call); + if (err) + goto out_unlock; + if (!strcmp(strstrip(filter_string), "0")) { filter_disable_preds(call); remove_filter_string(call->filter); @@ -1139,6 +1167,10 @@ int apply_subsystem_event_filter(struct event_subsystem *system, mutex_lock(&event_mutex); + err = init_subsystem_preds(system); + if (err) + goto out_unlock; + if (!strcmp(strstrip(filter_string), "0")) { filter_free_subsystem_preds(system, FILTER_DISABLE_ALL); remove_filter_string(system->filter); diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 029a91f..df1bf6e 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -135,7 +135,6 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ static int ftrace_raw_init_event_##call(void) \ { \ INIT_LIST_HEAD(&event_##call.fields); \ - init_preds(&event_##call); \ return 0; \ } \ -- cgit v1.1 From 41b6a95d693319f804607b559893fbbd27498548 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2009 09:59:48 -0400 Subject: ring-buffer: do not reset while in a commit The callers of reset must ensure that no commit can be taking place at the time of the reset. If it does then we may corrupt the ring buffer. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index da2c59d..79d6012 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3373,12 +3373,16 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu) spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing))) + goto out; + __raw_spin_lock(&cpu_buffer->lock); rb_reset_cpu(cpu_buffer); __raw_spin_unlock(&cpu_buffer->lock); + out: spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); atomic_dec(&cpu_buffer->record_disabled); -- cgit v1.1 From 98277991a99734f3a31d638afb47d4484ac73e43 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2009 10:56:15 -0400 Subject: ring-buffer: do not swap buffers during a commit If a commit is taking place on a CPU ring buffer, do not allow it to be swapped. Return -EBUSY when this is detected instead. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 79d6012..2878bd43 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3519,16 +3519,23 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, atomic_inc(&cpu_buffer_a->record_disabled); atomic_inc(&cpu_buffer_b->record_disabled); + ret = -EBUSY; + if (local_read(&cpu_buffer_a->committing)) + goto out_dec; + if (local_read(&cpu_buffer_b->committing)) + goto out_dec; + buffer_a->buffers[cpu] = cpu_buffer_b; buffer_b->buffers[cpu] = cpu_buffer_a; cpu_buffer_b->buffer = buffer_a; cpu_buffer_a->buffer = buffer_b; + ret = 0; + +out_dec: atomic_dec(&cpu_buffer_a->record_disabled); atomic_dec(&cpu_buffer_b->record_disabled); - - ret = 0; out: return ret; } -- cgit v1.1 From 1b959e18c4d6b4b981f887260b0f8e7939efa411 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 10:12:13 -0400 Subject: ring-buffer: remove unnecessary cpu_relax The loops in the ring buffer that use cpu_relax are not dependent on other CPUs. They simply came across some padding in the ring buffer and are skipping over them. It is a normal loop and does not require a cpu_relax. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 2878bd43..a05541a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3132,10 +3132,8 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts) spin_unlock(&cpu_buffer->reader_lock); local_irq_restore(flags); - if (event && event->type_len == RINGBUF_TYPE_PADDING) { - cpu_relax(); + if (event && event->type_len == RINGBUF_TYPE_PADDING) goto again; - } return event; } @@ -3160,10 +3158,8 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts) event = rb_iter_peek(iter, ts); spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); - if (event && event->type_len == RINGBUF_TYPE_PADDING) { - cpu_relax(); + if (event && event->type_len == RINGBUF_TYPE_PADDING) goto again; - } return event; } @@ -3209,10 +3205,8 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts) out: preempt_enable(); - if (event && event->type_len == RINGBUF_TYPE_PADDING) { - cpu_relax(); + if (event && event->type_len == RINGBUF_TYPE_PADDING) goto again; - } return event; } @@ -3302,10 +3296,8 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts) out: spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); - if (event && event->type_len == RINGBUF_TYPE_PADDING) { - cpu_relax(); + if (event && event->type_len == RINGBUF_TYPE_PADDING) goto again; - } return event; } -- cgit v1.1 From 7e9391cfedce34eb9786bfa69d7d545dc93ef930 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 10:02:09 -0400 Subject: ring-buffer: fix ring_buffer_read crossing pages When the ring buffer uses an iterator (static read mode, not on the fly reading), when it crosses a page boundery, it will skip the first entry on the next page. The reason is that the last entry of a page is usually padding if the page is not full. The padding will not be returned to the user. The problem arises on ring_buffer_read because it also increments the iterator. Because both the read and peek use the same rb_iter_peek, the rb_iter_peak will return the padding but also increment to the next item. This is because the ring_buffer_peek will not incerment it itself. The ring_buffer_read will increment it again and then call rb_iter_peek again to get the next item. But that will be the second item, not the first one on the page. The reason this never showed up before, is because the ftrace utility always calls ring_buffer_peek first and only uses ring_buffer_read to increment to the next item. The ring_buffer_peek will always keep the pointer to a valid item and not padding. This just hid the bug. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a05541a..9d939e7 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3286,19 +3286,19 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts) struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; unsigned long flags; - again: spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + again: event = rb_iter_peek(iter, ts); if (!event) goto out; + if (event->type_len == RINGBUF_TYPE_PADDING) + goto again; + rb_advance_iter(iter); out: spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); - if (event && event->type_len == RINGBUF_TYPE_PADDING) - goto again; - return event; } EXPORT_SYMBOL_GPL(ring_buffer_read); -- cgit v1.1 From dc892f7339af2d125478b800edb9081d6149665b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 15:33:41 -0400 Subject: ring-buffer: remove ring_buffer_event_discard The function ring_buffer_event_discard can be used on any item in the ring buffer, even after the item was committed. This function provides no safety nets and is very race prone. An item may be safely removed from the ring buffer before it is committed with the ring_buffer_discard_commit. Since there are currently no users of this function, and because this function is racey and error prone, this patch removes it altogether. Note, removing this function also allows the counters to ignore all discarded events (patches will follow). Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 27 ++++++--------------------- 1 file changed, 6 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 9d939e7..092fe0c 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2328,31 +2328,16 @@ static inline void rb_event_discard(struct ring_buffer_event *event) } /** - * ring_buffer_event_discard - discard any event in the ring buffer - * @event: the event to discard - * - * Sometimes a event that is in the ring buffer needs to be ignored. - * This function lets the user discard an event in the ring buffer - * and then that event will not be read later. - * - * Note, it is up to the user to be careful with this, and protect - * against races. If the user discards an event that has been consumed - * it is possible that it could corrupt the ring buffer. - */ -void ring_buffer_event_discard(struct ring_buffer_event *event) -{ - rb_event_discard(event); -} -EXPORT_SYMBOL_GPL(ring_buffer_event_discard); - -/** * ring_buffer_commit_discard - discard an event that has not been committed * @buffer: the ring buffer * @event: non committed event to discard * - * This is similar to ring_buffer_event_discard but must only be - * performed on an event that has not been committed yet. The difference - * is that this will also try to free the event from the ring buffer + * Sometimes an event that is in the ring buffer needs to be ignored. + * This function lets the user discard an event in the ring buffer + * and then that event will not be read later. + * + * This function only works if it is called before the the item has been + * committed. It will try to free the event from the ring buffer * if another event has not been added behind it. * * If another event has been added behind it, it will set the event -- cgit v1.1 From a1863c212b7517afc2b13e549552ac322fb44cab Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 10:23:58 -0400 Subject: ring-buffer: do not count discarded events The latency tracers report the number of items in the trace buffer. This uses the ring buffer data to calculate this. Because discarded events are also counted, the numbers do not match the number of items that are printed. The ring buffer also adds a "padding" item to the end of each buffer page which also gets counted as a discarded item. This patch decrements the counter to the page entries on a discard. This allows us to ignore discarded entries while reading the buffer. Decrementing the counter is still safe since it can only happen while the committing flag is still set. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 71 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 54 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 092fe0c..c8d2a66 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -218,17 +218,12 @@ enum { static inline int rb_null_event(struct ring_buffer_event *event) { - return event->type_len == RINGBUF_TYPE_PADDING - && event->time_delta == 0; -} - -static inline int rb_discarded_event(struct ring_buffer_event *event) -{ - return event->type_len == RINGBUF_TYPE_PADDING && event->time_delta; + return event->type_len == RINGBUF_TYPE_PADDING && !event->time_delta; } static void rb_event_set_padding(struct ring_buffer_event *event) { + /* padding has a NULL time_delta */ event->type_len = RINGBUF_TYPE_PADDING; event->time_delta = 0; } @@ -1778,9 +1773,6 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer, event->type_len = RINGBUF_TYPE_PADDING; /* time delta must be non zero */ event->time_delta = 1; - /* Account for this as an entry */ - local_inc(&tail_page->entries); - local_inc(&cpu_buffer->entries); /* Set write to end of buffer */ length = (tail + length) - BUF_PAGE_SIZE; @@ -2269,18 +2261,23 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length) } EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve); -static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer, +static void +rb_update_write_stamp(struct ring_buffer_per_cpu *cpu_buffer, struct ring_buffer_event *event) { - local_inc(&cpu_buffer->entries); - /* * The event first in the commit queue updates the * time stamp. */ if (rb_event_is_commit(cpu_buffer, event)) cpu_buffer->write_stamp += event->time_delta; +} +static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer, + struct ring_buffer_event *event) +{ + local_inc(&cpu_buffer->entries); + rb_update_write_stamp(cpu_buffer, event); rb_end_commit(cpu_buffer); } @@ -2327,6 +2324,46 @@ static inline void rb_event_discard(struct ring_buffer_event *event) event->time_delta = 1; } +/* + * Decrement the entries to the page that an event is on. + * The event does not even need to exist, only the pointer + * to the page it is on. This may only be called before the commit + * takes place. + */ +static inline void +rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer, + struct ring_buffer_event *event) +{ + unsigned long addr = (unsigned long)event; + struct buffer_page *bpage = cpu_buffer->commit_page; + struct buffer_page *start; + + addr &= PAGE_MASK; + + /* Do the likely case first */ + if (likely(bpage->page == (void *)addr)) { + local_dec(&bpage->entries); + return; + } + + /* + * Because the commit page may be on the reader page we + * start with the next page and check the end loop there. + */ + rb_inc_page(cpu_buffer, &bpage); + start = bpage; + do { + if (bpage->page == (void *)addr) { + local_dec(&bpage->entries); + return; + } + rb_inc_page(cpu_buffer, &bpage); + } while (bpage != start); + + /* commit not part of this buffer?? */ + RB_WARN_ON(cpu_buffer, 1); +} + /** * ring_buffer_commit_discard - discard an event that has not been committed * @buffer: the ring buffer @@ -2365,14 +2402,15 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer, */ RB_WARN_ON(buffer, !local_read(&cpu_buffer->committing)); + rb_decrement_entry(cpu_buffer, event); if (rb_try_to_discard(cpu_buffer, event)) goto out; /* * The commit is still visible by the reader, so we - * must increment entries. + * must still update the timestamp. */ - local_inc(&cpu_buffer->entries); + rb_update_write_stamp(cpu_buffer, event); out: rb_end_commit(cpu_buffer); @@ -2884,8 +2922,7 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer) event = rb_reader_event(cpu_buffer); - if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX - || rb_discarded_event(event)) + if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX) cpu_buffer->read++; rb_update_read_stamp(cpu_buffer, event); -- cgit v1.1 From 077c5407cd3231cf13472623995f0dfdda510d62 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 19:53:46 -0400 Subject: ring-buffer: disable all cpu buffers when one finds a problem Currently the way RB_WARN_ON works, is to disable either the current CPU buffer or all CPU buffers, depending on whether a ring_buffer or ring_buffer_per_cpu struct was passed into the macro. Most users of the RB_WARN_ON pass in the CPU buffer, so only the one CPU buffer gets disabled but the rest are still active. This may confuse users even though a warning is sent to the console. This patch changes the macro to disable the entire buffer even if the CPU buffer is passed in. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c8d2a66..f83a42a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -467,14 +467,19 @@ struct ring_buffer_iter { }; /* buffer may be either ring_buffer or ring_buffer_per_cpu */ -#define RB_WARN_ON(buffer, cond) \ - ({ \ - int _____ret = unlikely(cond); \ - if (_____ret) { \ - atomic_inc(&buffer->record_disabled); \ - WARN_ON(1); \ - } \ - _____ret; \ +#define RB_WARN_ON(b, cond) \ + ({ \ + int _____ret = unlikely(cond); \ + if (_____ret) { \ + if (__same_type(*(b), struct ring_buffer_per_cpu)) { \ + struct ring_buffer_per_cpu *__b = \ + (void *)b; \ + atomic_inc(&__b->buffer->record_disabled); \ + } else \ + atomic_inc(&b->record_disabled); \ + WARN_ON(1); \ + } \ + _____ret; \ }) /* Up this if you want to test the TIME_EXTENTS and normalization */ -- cgit v1.1 From 8248ac052dfd1eb41819fbc0ca5c7a1667e7e70c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2009 12:27:41 -0400 Subject: tracing: print out start and stop in latency traces During development of the tracer, we would copy information from the live tracer to the max tracer with one memcpy. Since then we added a generic ring buffer and we handle the copies differently now. Unfortunately, we never copied the critical section information, and we lost the output: # => started at: kmem_cache_alloc # => ended at: kmem_cache_alloc This patch adds back the critical start and end copying as well as removes the unused "trace_idx" and "overrun" fields of the trace_array_cpu structure. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 19 +++++++++++-------- kernel/trace/trace.h | 3 --- 2 files changed, 11 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0f08816..df2c9f7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -407,19 +407,22 @@ static void __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct trace_array_cpu *data = tr->data[cpu]; + struct trace_array_cpu *max_data = tr->data[cpu]; max_tr.cpu = cpu; max_tr.time_start = data->preempt_timestamp; - data = max_tr.data[cpu]; - data->saved_latency = tracing_max_latency; + max_data = max_tr.data[cpu]; + max_data->saved_latency = tracing_max_latency; + max_data->critical_start = data->critical_start; + max_data->critical_end = data->critical_end; memcpy(data->comm, tsk->comm, TASK_COMM_LEN); - data->pid = tsk->pid; - data->uid = task_uid(tsk); - data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; - data->policy = tsk->policy; - data->rt_priority = tsk->rt_priority; + max_data->pid = tsk->pid; + max_data->uid = task_uid(tsk); + max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; + max_data->policy = tsk->policy; + max_data->rt_priority = tsk->rt_priority; /* record this tasks comm */ tracing_record_cmdline(tsk); @@ -1501,7 +1504,7 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter) seq_puts(m, "\n# => ended at: "); seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags); trace_print_seq(m, &iter->seq); - seq_puts(m, "#\n"); + seq_puts(m, "\n#\n"); } seq_puts(m, "#\n"); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index e2c06b2..f2af713 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -234,9 +234,6 @@ struct trace_array_cpu { atomic_t disabled; void *buffer_page; /* ring buffer spare */ - /* these fields get copied into max-trace: */ - unsigned long trace_idx; - unsigned long overrun; unsigned long saved_latency; unsigned long critical_start; unsigned long critical_end; -- cgit v1.1 From b8de7bd168fa54d059b16d3057b2f8a32cc5bdc3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 31 Aug 2009 22:32:27 -0400 Subject: tracing: disable update max tracer while reading trace When reading the tracer from the trace file, updating the max latency may corrupt the output. This patch disables the tracing of the max latency while reading the trace file. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index df2c9f7..e521f1e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -263,6 +263,9 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME | TRACE_ITER_GRAPH_TIME; +static int trace_stop_count; +static DEFINE_SPINLOCK(tracing_start_lock); + /** * trace_wake_up - wake up tasks waiting for trace input * @@ -442,6 +445,9 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct ring_buffer *buf = tr->buffer; + if (trace_stop_count) + return; + WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); @@ -469,6 +475,9 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) { int ret; + if (trace_stop_count) + return; + WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); @@ -685,9 +694,6 @@ static void trace_init_cmdlines(void) cmdline_idx = 0; } -static int trace_stop_count; -static DEFINE_SPINLOCK(tracing_start_lock); - /** * ftrace_off_permanent - disable all ftrace code permanently * -- cgit v1.1 From 621968cdb2563b667d6ecb484ba91ef4c3a797b3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 4 Sep 2009 12:02:35 -0400 Subject: tracing: disable buffers and synchronize_sched before resetting Resetting the ring buffers while traces are happening can corrupt the ring buffer and disable it (no kernel crash to worry about). The safest thing to do is disable the ring buffers, call synchronize_sched() to wait for all current writers to finish and then reset the buffer. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e521f1e..9110329 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -658,12 +658,20 @@ void tracing_reset(struct trace_array *tr, int cpu) void tracing_reset_online_cpus(struct trace_array *tr) { + struct ring_buffer *buffer = tr->buffer; int cpu; + ring_buffer_record_disable(buffer); + + /* Make sure all commits have finished */ + synchronize_sched(); + tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) tracing_reset(tr, cpu); + + ring_buffer_record_enable(buffer); } void tracing_reset_current(int cpu) -- cgit v1.1 From 76f0d07376388f32698ba51b6090a26b90c1342f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 4 Sep 2009 12:12:39 -0400 Subject: tracing: remove users of tracing_reset The function tracing_reset is deprecated for outside use of trace.c. The new function to reset the the buffers is tracing_reset_online_cpus. The reason for this is that resetting the buffers while the event trace points are active can corrupt the buffers, because they may be writing at the time of reset. The tracing_reset_online_cpus disables writes and waits for current writers to finish. This patch replaces all users of tracing_reset except for the latency tracers. Those changes require more work and will be removed in the following patches. Signed-off-by: Steven Rostedt --- kernel/trace/kmemtrace.c | 4 +--- kernel/trace/trace.c | 7 ++----- kernel/trace/trace_boot.c | 4 +--- kernel/trace/trace_power.c | 4 +--- 4 files changed, 5 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/kmemtrace.c b/kernel/trace/kmemtrace.c index dda53cc..81b1645 100644 --- a/kernel/trace/kmemtrace.c +++ b/kernel/trace/kmemtrace.c @@ -183,11 +183,9 @@ static void kmemtrace_stop_probes(void) static int kmem_trace_init(struct trace_array *tr) { - int cpu; kmemtrace_array = tr; - for_each_cpu(cpu, cpu_possible_mask) - tracing_reset(tr, cpu); + tracing_reset_online_cpus(tr); kmemtrace_start_probes(); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9110329..54517a8 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -550,7 +550,6 @@ __acquires(kernel_lock) if (type->selftest && !tracing_selftest_disabled) { struct tracer *saved_tracer = current_trace; struct trace_array *tr = &global_trace; - int i; /* * Run a selftest on this tracer. @@ -559,8 +558,7 @@ __acquires(kernel_lock) * internal tracing to verify that everything is in order. * If we fail, we do not register this tracer. */ - for_each_tracing_cpu(i) - tracing_reset(tr, i); + tracing_reset_online_cpus(tr); current_trace = type; /* the test is responsible for initializing and enabling */ @@ -573,8 +571,7 @@ __acquires(kernel_lock) goto out; } /* Only reset on passing, to avoid touching corrupted buffers */ - for_each_tracing_cpu(i) - tracing_reset(tr, i); + tracing_reset_online_cpus(tr); printk(KERN_CONT "PASSED\n"); } diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index a29ef23..8631393 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -41,14 +41,12 @@ void disable_boot_trace(void) static int boot_trace_init(struct trace_array *tr) { - int cpu; boot_trace = tr; if (!tr) return 0; - for_each_cpu(cpu, cpu_possible_mask) - tracing_reset(tr, cpu); + tracing_reset_online_cpus(tr); tracing_sched_switch_assign_trace(tr); return 0; diff --git a/kernel/trace/trace_power.c b/kernel/trace/trace_power.c index 8a30d98..a5d5a4f 100644 --- a/kernel/trace/trace_power.c +++ b/kernel/trace/trace_power.c @@ -144,14 +144,12 @@ static void power_trace_reset(struct trace_array *tr) static int power_trace_init(struct trace_array *tr) { - int cpu; power_trace = tr; trace_power_enabled = 1; tracing_power_register(); - for_each_cpu(cpu, cpu_possible_mask) - tracing_reset(tr, cpu); + tracing_reset_online_cpus(tr); return 0; } -- cgit v1.1 From c58b43218c1a04a0bcf338ea47406c759ac28e11 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 1 Sep 2009 13:31:38 +0800 Subject: tracing/filters: Defer pred allocation, fix memory leak The predicates of an event and their filter structure are allocated when we create an event filter for the first time. These objects must be created once but each time we come with a new filter, we overwrite such pre-existing allocation, if any. Thus, this patch checks if the filter has already been allocated before going ahead. Spotted-by: Frederic Weisbecker Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Tom Zanussi Cc: Masami Hiramatsu LKML-Reference: <4A9CB1BA.3060402@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace_events_filter.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index c6b2edf..93660fb 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -409,6 +409,9 @@ static int init_preds(struct ftrace_event_call *call) struct filter_pred *pred; int i; + if (call->filter) + return 0; + filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL); if (!call->filter) return -ENOMEM; @@ -447,11 +450,9 @@ static int init_subsystem_preds(struct event_subsystem *system) if (strcmp(call->system, system->name) != 0) continue; - if (!call->filter) { - err = init_preds(call); - if (err) - return err; - } + err = init_preds(call); + if (err) + return err; } return 0; -- cgit v1.1 From 2f26ebd549b9ab55ac756b836ec759c11fe93f81 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 1 Sep 2009 11:06:29 -0400 Subject: tracing: use timestamp to determine start of latency traces Currently the latency tracers reset the ring buffer. Unfortunately if a commit is in process (due to a trace event), this can corrupt the ring buffer. When this happens, the ring buffer will detect the corruption and then permanently disable the ring buffer. The bug does not crash the system, but it does prevent further tracing after the bug is hit. Instead of reseting the trace buffers, the timestamp of the start of the trace is used instead. The buffers will still contain the previous data, but the output will not count any data that is before the timestamp of the trace. Note, this only affects the static trace output (trace) and not the runtime trace output (trace_pipe). The runtime trace output does not make sense for the latency tracers anyway. Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 80 ++++++++++++++++++++++++++++++--------- kernel/trace/trace.h | 1 + kernel/trace/trace_irqsoff.c | 3 +- kernel/trace/trace_sched_wakeup.c | 7 +--- 4 files changed, 67 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 54517a8..7daf372 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -454,10 +454,6 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) tr->buffer = max_tr.buffer; max_tr.buffer = buf; - ftrace_disable_cpu(); - ring_buffer_reset(tr->buffer); - ftrace_enable_cpu(); - __update_max_tr(tr, tsk, cpu); __raw_spin_unlock(&ftrace_max_lock); } @@ -483,7 +479,6 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) ftrace_disable_cpu(); - ring_buffer_reset(max_tr.buffer); ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu); ftrace_enable_cpu(); @@ -1374,6 +1369,37 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos) return ent; } +static void tracing_iter_reset(struct trace_iterator *iter, int cpu) +{ + struct trace_array *tr = iter->tr; + struct ring_buffer_event *event; + struct ring_buffer_iter *buf_iter; + unsigned long entries = 0; + u64 ts; + + tr->data[cpu]->skipped_entries = 0; + + if (!iter->buffer_iter[cpu]) + return; + + buf_iter = iter->buffer_iter[cpu]; + ring_buffer_iter_reset(buf_iter); + + /* + * We could have the case with the max latency tracers + * that a reset never took place on a cpu. This is evident + * by the timestamp being before the start of the buffer. + */ + while ((event = ring_buffer_iter_peek(buf_iter, &ts))) { + if (ts >= iter->tr->time_start) + break; + entries++; + ring_buffer_read(buf_iter, NULL); + } + + tr->data[cpu]->skipped_entries = entries; +} + /* * No necessary locking here. The worst thing which can * happen is loosing events consumed at the same time @@ -1412,10 +1438,9 @@ static void *s_start(struct seq_file *m, loff_t *pos) if (cpu_file == TRACE_PIPE_ALL_CPU) { for_each_tracing_cpu(cpu) - ring_buffer_iter_reset(iter->buffer_iter[cpu]); + tracing_iter_reset(iter, cpu); } else - ring_buffer_iter_reset(iter->buffer_iter[cpu_file]); - + tracing_iter_reset(iter, cpu_file); ftrace_enable_cpu(); @@ -1464,16 +1489,32 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter) struct trace_array *tr = iter->tr; struct trace_array_cpu *data = tr->data[tr->cpu]; struct tracer *type = current_trace; - unsigned long total; - unsigned long entries; + unsigned long entries = 0; + unsigned long total = 0; + unsigned long count; const char *name = "preemption"; + int cpu; if (type) name = type->name; - entries = ring_buffer_entries(iter->tr->buffer); - total = entries + - ring_buffer_overruns(iter->tr->buffer); + + for_each_tracing_cpu(cpu) { + count = ring_buffer_entries_cpu(tr->buffer, cpu); + /* + * If this buffer has skipped entries, then we hold all + * entries for the trace and we need to ignore the + * ones before the time stamp. + */ + if (tr->data[cpu]->skipped_entries) { + count -= tr->data[cpu]->skipped_entries; + /* total is the same as the entries */ + total += count; + } else + total += count + + ring_buffer_overrun_cpu(tr->buffer, cpu); + entries += count; + } seq_printf(m, "# %s latency trace v1.1.5 on %s\n", name, UTS_RELEASE); @@ -1534,6 +1575,9 @@ static void test_cpu_buff_start(struct trace_iterator *iter) if (cpumask_test_cpu(iter->cpu, iter->started)) return; + if (iter->tr->data[iter->cpu]->skipped_entries) + return; + cpumask_set_cpu(iter->cpu, iter->started); /* Don't print started cpu buffer for the first entry of the trace */ @@ -1796,19 +1840,23 @@ __tracing_open(struct inode *inode, struct file *file) if (ring_buffer_overruns(iter->tr->buffer)) iter->iter_flags |= TRACE_FILE_ANNOTATE; + /* stop the trace while dumping */ + tracing_stop(); + if (iter->cpu_file == TRACE_PIPE_ALL_CPU) { for_each_tracing_cpu(cpu) { iter->buffer_iter[cpu] = ring_buffer_read_start(iter->tr->buffer, cpu); + tracing_iter_reset(iter, cpu); } } else { cpu = iter->cpu_file; iter->buffer_iter[cpu] = ring_buffer_read_start(iter->tr->buffer, cpu); + tracing_iter_reset(iter, cpu); } - /* TODO stop tracer */ ret = seq_open(file, &tracer_seq_ops); if (ret < 0) { fail_ret = ERR_PTR(ret); @@ -1818,9 +1866,6 @@ __tracing_open(struct inode *inode, struct file *file) m = file->private_data; m->private = iter; - /* stop the trace while dumping */ - tracing_stop(); - mutex_unlock(&trace_types_lock); return iter; @@ -1831,6 +1876,7 @@ __tracing_open(struct inode *inode, struct file *file) ring_buffer_read_finish(iter->buffer_iter[cpu]); } free_cpumask_var(iter->started); + tracing_start(); fail: mutex_unlock(&trace_types_lock); kfree(iter->trace); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f2af713..ca070de 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -241,6 +241,7 @@ struct trace_array_cpu { unsigned long nice; unsigned long policy; unsigned long rt_priority; + unsigned long skipped_entries; cycle_t preempt_timestamp; pid_t pid; uid_t uid; diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index b923d13..5555b75 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -178,7 +178,6 @@ out_unlock: out: data->critical_sequence = max_sequence; data->preempt_timestamp = ftrace_now(cpu); - tracing_reset(tr, cpu); trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); } @@ -208,7 +207,6 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) data->critical_sequence = max_sequence; data->preempt_timestamp = ftrace_now(cpu); data->critical_start = parent_ip ? : ip; - tracing_reset(tr, cpu); local_save_flags(flags); @@ -379,6 +377,7 @@ static void __irqsoff_tracer_init(struct trace_array *tr) irqsoff_trace = tr; /* make sure that the tracer is visible */ smp_wmb(); + tracing_reset_online_cpus(tr); start_irqsoff_tracer(tr); } diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index eacb272..ad69f10 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -186,11 +186,6 @@ out: static void __wakeup_reset(struct trace_array *tr) { - int cpu; - - for_each_possible_cpu(cpu) - tracing_reset(tr, cpu); - wakeup_cpu = -1; wakeup_prio = -1; @@ -204,6 +199,8 @@ static void wakeup_reset(struct trace_array *tr) { unsigned long flags; + tracing_reset_online_cpus(tr); + local_irq_save(flags); __raw_spin_lock(&wakeup_lock); __wakeup_reset(tr); -- cgit v1.1 From f633903af2ceb0cec07d45e499a072b6593d0ed1 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 4 Sep 2009 12:35:16 -0400 Subject: tracing: make tracing_reset safe for external use Reseting the trace buffer without first disabling the buffer and waiting for any writers to complete, can corrupt the ring buffer. This patch makes the external version of tracing_reset safe from corruption by disabling the ring buffer and calling synchronize_sched. This version can no longer be called from interrupt context. But all those callers have been removed. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7daf372..0418e26 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -641,13 +641,26 @@ void unregister_tracer(struct tracer *type) mutex_unlock(&trace_types_lock); } -void tracing_reset(struct trace_array *tr, int cpu) +static void __tracing_reset(struct trace_array *tr, int cpu) { ftrace_disable_cpu(); ring_buffer_reset_cpu(tr->buffer, cpu); ftrace_enable_cpu(); } +void tracing_reset(struct trace_array *tr, int cpu) +{ + struct ring_buffer *buffer = tr->buffer; + + ring_buffer_record_disable(buffer); + + /* Make sure all commits have finished */ + synchronize_sched(); + __tracing_reset(tr, cpu); + + ring_buffer_record_enable(buffer); +} + void tracing_reset_online_cpus(struct trace_array *tr) { struct ring_buffer *buffer = tr->buffer; @@ -661,7 +674,7 @@ void tracing_reset_online_cpus(struct trace_array *tr) tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) - tracing_reset(tr, cpu); + __tracing_reset(tr, cpu); ring_buffer_record_enable(buffer); } -- cgit v1.1 From e77405ad80f53966524b5c31244e13fbbbecbd84 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2009 14:17:06 -0400 Subject: tracing: pass around ring buffer instead of tracer The latency tracers (irqsoff and wakeup) can swap trace buffers on the fly. If an event is happening and has reserved data on one of the buffers, and the latency tracer swaps the global buffer with the max buffer, the result is that the event may commit the data to the wrong buffer. This patch changes the API to the trace recording to be recieve the buffer that was used to reserve a commit. Then this buffer can be passed in to the commit. Signed-off-by: Steven Rostedt --- kernel/trace/blktrace.c | 12 ++-- kernel/trace/trace.c | 117 ++++++++++++++++++++--------------- kernel/trace/trace.h | 17 ++--- kernel/trace/trace_boot.c | 12 ++-- kernel/trace/trace_events.c | 6 +- kernel/trace/trace_functions_graph.c | 14 +++-- kernel/trace/trace_mmiotrace.c | 10 +-- kernel/trace/trace_power.c | 18 ++++-- kernel/trace/trace_sched_switch.c | 18 +++--- kernel/trace/trace_syscalls.c | 18 +++--- 10 files changed, 143 insertions(+), 99 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 1090b0a..243bafc 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -65,13 +65,15 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action, { struct blk_io_trace *t; struct ring_buffer_event *event = NULL; + struct ring_buffer *buffer = NULL; int pc = 0; int cpu = smp_processor_id(); bool blk_tracer = blk_tracer_enabled; if (blk_tracer) { + buffer = blk_tr->buffer; pc = preempt_count(); - event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK, + event = trace_buffer_lock_reserve(buffer, TRACE_BLK, sizeof(*t) + len, 0, pc); if (!event) @@ -96,7 +98,7 @@ record_it: memcpy((void *) t + sizeof(*t), data, len); if (blk_tracer) - trace_buffer_unlock_commit(blk_tr, event, 0, pc); + trace_buffer_unlock_commit(buffer, event, 0, pc); } } @@ -179,6 +181,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, { struct task_struct *tsk = current; struct ring_buffer_event *event = NULL; + struct ring_buffer *buffer = NULL; struct blk_io_trace *t; unsigned long flags = 0; unsigned long *sequence; @@ -204,8 +207,9 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, if (blk_tracer) { tracing_record_cmdline(current); + buffer = blk_tr->buffer; pc = preempt_count(); - event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK, + event = trace_buffer_lock_reserve(buffer, TRACE_BLK, sizeof(*t) + pdu_len, 0, pc); if (!event) @@ -252,7 +256,7 @@ record_it: memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); if (blk_tracer) { - trace_buffer_unlock_commit(blk_tr, event, 0, pc); + trace_buffer_unlock_commit(buffer, event, 0, pc); return; } } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0418e26..0c61836 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -169,10 +169,11 @@ static struct trace_array global_trace; static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu); -int filter_current_check_discard(struct ftrace_event_call *call, void *rec, +int filter_current_check_discard(struct ring_buffer *buffer, + struct ftrace_event_call *call, void *rec, struct ring_buffer_event *event) { - return filter_check_discard(call, rec, global_trace.buffer, event); + return filter_check_discard(call, rec, buffer, event); } EXPORT_SYMBOL_GPL(filter_current_check_discard); @@ -887,14 +888,15 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, } EXPORT_SYMBOL_GPL(tracing_generic_entry_update); -struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr, - int type, - unsigned long len, - unsigned long flags, int pc) +struct ring_buffer_event * +trace_buffer_lock_reserve(struct ring_buffer *buffer, + int type, + unsigned long len, + unsigned long flags, int pc) { struct ring_buffer_event *event; - event = ring_buffer_lock_reserve(tr->buffer, len); + event = ring_buffer_lock_reserve(buffer, len); if (event != NULL) { struct trace_entry *ent = ring_buffer_event_data(event); @@ -905,53 +907,59 @@ struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr, return event; } -static inline void __trace_buffer_unlock_commit(struct trace_array *tr, - struct ring_buffer_event *event, - unsigned long flags, int pc, - int wake) +static inline void +__trace_buffer_unlock_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc, + int wake) { - ring_buffer_unlock_commit(tr->buffer, event); + ring_buffer_unlock_commit(buffer, event); - ftrace_trace_stack(tr, flags, 6, pc); - ftrace_trace_userstack(tr, flags, pc); + ftrace_trace_stack(buffer, flags, 6, pc); + ftrace_trace_userstack(buffer, flags, pc); if (wake) trace_wake_up(); } -void trace_buffer_unlock_commit(struct trace_array *tr, - struct ring_buffer_event *event, - unsigned long flags, int pc) +void trace_buffer_unlock_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc) { - __trace_buffer_unlock_commit(tr, event, flags, pc, 1); + __trace_buffer_unlock_commit(buffer, event, flags, pc, 1); } struct ring_buffer_event * -trace_current_buffer_lock_reserve(int type, unsigned long len, +trace_current_buffer_lock_reserve(struct ring_buffer **current_rb, + int type, unsigned long len, unsigned long flags, int pc) { - return trace_buffer_lock_reserve(&global_trace, + *current_rb = global_trace.buffer; + return trace_buffer_lock_reserve(*current_rb, type, len, flags, pc); } EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve); -void trace_current_buffer_unlock_commit(struct ring_buffer_event *event, +void trace_current_buffer_unlock_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event, unsigned long flags, int pc) { - __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1); + __trace_buffer_unlock_commit(buffer, event, flags, pc, 1); } EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit); -void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event, - unsigned long flags, int pc) +void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc) { - __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0); + __trace_buffer_unlock_commit(buffer, event, flags, pc, 0); } EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit); -void trace_current_buffer_discard_commit(struct ring_buffer_event *event) +void trace_current_buffer_discard_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event) { - ring_buffer_discard_commit(global_trace.buffer, event); + ring_buffer_discard_commit(buffer, event); } EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit); @@ -961,6 +969,7 @@ trace_function(struct trace_array *tr, int pc) { struct ftrace_event_call *call = &event_function; + struct ring_buffer *buffer = tr->buffer; struct ring_buffer_event *event; struct ftrace_entry *entry; @@ -968,7 +977,7 @@ trace_function(struct trace_array *tr, if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; - event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry), + event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry), flags, pc); if (!event) return; @@ -976,8 +985,8 @@ trace_function(struct trace_array *tr, entry->ip = ip; entry->parent_ip = parent_ip; - if (!filter_check_discard(call, entry, tr->buffer, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); } void @@ -990,7 +999,7 @@ ftrace(struct trace_array *tr, struct trace_array_cpu *data, } #ifdef CONFIG_STACKTRACE -static void __ftrace_trace_stack(struct trace_array *tr, +static void __ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, int skip, int pc) { @@ -999,7 +1008,7 @@ static void __ftrace_trace_stack(struct trace_array *tr, struct stack_entry *entry; struct stack_trace trace; - event = trace_buffer_lock_reserve(tr, TRACE_STACK, + event = trace_buffer_lock_reserve(buffer, TRACE_STACK, sizeof(*entry), flags, pc); if (!event) return; @@ -1012,26 +1021,27 @@ static void __ftrace_trace_stack(struct trace_array *tr, trace.entries = entry->caller; save_stack_trace(&trace); - if (!filter_check_discard(call, entry, tr->buffer, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); } -void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, int skip, - int pc) +void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, + int skip, int pc) { if (!(trace_flags & TRACE_ITER_STACKTRACE)) return; - __ftrace_trace_stack(tr, flags, skip, pc); + __ftrace_trace_stack(buffer, flags, skip, pc); } void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc) { - __ftrace_trace_stack(tr, flags, skip, pc); + __ftrace_trace_stack(tr->buffer, flags, skip, pc); } -void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc) +void +ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_user_stack; struct ring_buffer_event *event; @@ -1041,7 +1051,7 @@ void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc) if (!(trace_flags & TRACE_ITER_USERSTACKTRACE)) return; - event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK, + event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, sizeof(*entry), flags, pc); if (!event) return; @@ -1055,8 +1065,8 @@ void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc) trace.entries = entry->caller; save_stack_trace_user(&trace); - if (!filter_check_discard(call, entry, tr->buffer, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); } #ifdef UNUSED @@ -1075,9 +1085,10 @@ ftrace_trace_special(void *__tr, { struct ring_buffer_event *event; struct trace_array *tr = __tr; + struct ring_buffer *buffer = tr->buffer; struct special_entry *entry; - event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL, + event = trace_buffer_lock_reserve(buffer, TRACE_SPECIAL, sizeof(*entry), 0, pc); if (!event) return; @@ -1085,7 +1096,7 @@ ftrace_trace_special(void *__tr, entry->arg1 = arg1; entry->arg2 = arg2; entry->arg3 = arg3; - trace_buffer_unlock_commit(tr, event, 0, pc); + trace_buffer_unlock_commit(buffer, event, 0, pc); } void @@ -1131,6 +1142,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) struct ftrace_event_call *call = &event_bprint; struct ring_buffer_event *event; + struct ring_buffer *buffer; struct trace_array *tr = &global_trace; struct trace_array_cpu *data; struct bprint_entry *entry; @@ -1163,7 +1175,9 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) goto out_unlock; size = sizeof(*entry) + sizeof(u32) * len; - event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc); + buffer = tr->buffer; + event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, + flags, pc); if (!event) goto out_unlock; entry = ring_buffer_event_data(event); @@ -1171,8 +1185,8 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) entry->fmt = fmt; memcpy(entry->buf, trace_buf, sizeof(u32) * len); - if (!filter_check_discard(call, entry, tr->buffer, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); out_unlock: __raw_spin_unlock(&trace_buf_lock); @@ -1194,6 +1208,7 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) struct ftrace_event_call *call = &event_print; struct ring_buffer_event *event; + struct ring_buffer *buffer; struct trace_array *tr = &global_trace; struct trace_array_cpu *data; int cpu, len = 0, size, pc; @@ -1222,7 +1237,9 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) trace_buf[len] = 0; size = sizeof(*entry) + len + 1; - event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc); + buffer = tr->buffer; + event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, + irq_flags, pc); if (!event) goto out_unlock; entry = ring_buffer_event_data(event); @@ -1230,8 +1247,8 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) memcpy(&entry->buf, trace_buf, len); entry->buf[len] = 0; - if (!filter_check_discard(call, entry, tr->buffer, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); out_unlock: __raw_spin_unlock(&trace_buf_lock); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ca070de..4d30414 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -415,12 +415,13 @@ void init_tracer_sysprof_debugfs(struct dentry *d_tracer); struct ring_buffer_event; -struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr, - int type, - unsigned long len, - unsigned long flags, - int pc); -void trace_buffer_unlock_commit(struct trace_array *tr, +struct ring_buffer_event * +trace_buffer_lock_reserve(struct ring_buffer *buffer, + int type, + unsigned long len, + unsigned long flags, + int pc); +void trace_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc); @@ -481,10 +482,10 @@ void update_max_tr_single(struct trace_array *tr, #endif /* CONFIG_TRACER_MAX_TRACE */ #ifdef CONFIG_STACKTRACE -void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, +void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, int skip, int pc); -void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, +void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc); void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 8631393..19bfc75 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -130,6 +130,7 @@ struct tracer boot_tracer __read_mostly = void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) { struct ring_buffer_event *event; + struct ring_buffer *buffer; struct trace_boot_call *entry; struct trace_array *tr = boot_trace; @@ -142,13 +143,14 @@ void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) sprint_symbol(bt->func, (unsigned long)fn); preempt_disable(); - event = trace_buffer_lock_reserve(tr, TRACE_BOOT_CALL, + buffer = tr->buffer; + event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_CALL, sizeof(*entry), 0, 0); if (!event) goto out; entry = ring_buffer_event_data(event); entry->boot_call = *bt; - trace_buffer_unlock_commit(tr, event, 0, 0); + trace_buffer_unlock_commit(buffer, event, 0, 0); out: preempt_enable(); } @@ -156,6 +158,7 @@ void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn) { struct ring_buffer_event *event; + struct ring_buffer *buffer; struct trace_boot_ret *entry; struct trace_array *tr = boot_trace; @@ -165,13 +168,14 @@ void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn) sprint_symbol(bt->func, (unsigned long)fn); preempt_disable(); - event = trace_buffer_lock_reserve(tr, TRACE_BOOT_RET, + buffer = tr->buffer; + event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_RET, sizeof(*entry), 0, 0); if (!event) goto out; entry = ring_buffer_event_data(event); entry->boot_ret = *bt; - trace_buffer_unlock_commit(tr, event, 0, 0); + trace_buffer_unlock_commit(buffer, event, 0, 0); out: preempt_enable(); } diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index d33bcde..78b1ed2 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1438,6 +1438,7 @@ static void function_test_events_call(unsigned long ip, unsigned long parent_ip) { struct ring_buffer_event *event; + struct ring_buffer *buffer; struct ftrace_entry *entry; unsigned long flags; long disabled; @@ -1455,7 +1456,8 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip) local_save_flags(flags); - event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry), + event = trace_current_buffer_lock_reserve(&buffer, + TRACE_FN, sizeof(*entry), flags, pc); if (!event) goto out; @@ -1463,7 +1465,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip) entry->ip = ip; entry->parent_ip = parent_ip; - trace_nowake_buffer_unlock_commit(event, flags, pc); + trace_nowake_buffer_unlock_commit(buffer, event, flags, pc); out: atomic_dec(&per_cpu(test_event_disable, cpu)); diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 3f4a251..b3749a2 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -173,19 +173,20 @@ static int __trace_graph_entry(struct trace_array *tr, { struct ftrace_event_call *call = &event_funcgraph_entry; struct ring_buffer_event *event; + struct ring_buffer *buffer = tr->buffer; struct ftrace_graph_ent_entry *entry; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return 0; - event = trace_buffer_lock_reserve(tr, TRACE_GRAPH_ENT, + event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT, sizeof(*entry), flags, pc); if (!event) return 0; entry = ring_buffer_event_data(event); entry->graph_ent = *trace; - if (!filter_current_check_discard(call, entry, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_current_check_discard(buffer, call, entry, event)) + ring_buffer_unlock_commit(buffer, event); return 1; } @@ -236,19 +237,20 @@ static void __trace_graph_return(struct trace_array *tr, { struct ftrace_event_call *call = &event_funcgraph_exit; struct ring_buffer_event *event; + struct ring_buffer *buffer = tr->buffer; struct ftrace_graph_ret_entry *entry; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; - event = trace_buffer_lock_reserve(tr, TRACE_GRAPH_RET, + event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ret = *trace; - if (!filter_current_check_discard(call, entry, event)) - ring_buffer_unlock_commit(tr->buffer, event); + if (!filter_current_check_discard(buffer, call, entry, event)) + ring_buffer_unlock_commit(buffer, event); } void trace_graph_return(struct ftrace_graph_ret *trace) diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c index d53b45e..c4c9bbd 100644 --- a/kernel/trace/trace_mmiotrace.c +++ b/kernel/trace/trace_mmiotrace.c @@ -307,11 +307,12 @@ static void __trace_mmiotrace_rw(struct trace_array *tr, struct trace_array_cpu *data, struct mmiotrace_rw *rw) { + struct ring_buffer *buffer = tr->buffer; struct ring_buffer_event *event; struct trace_mmiotrace_rw *entry; int pc = preempt_count(); - event = trace_buffer_lock_reserve(tr, TRACE_MMIO_RW, + event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW, sizeof(*entry), 0, pc); if (!event) { atomic_inc(&dropped_count); @@ -319,7 +320,7 @@ static void __trace_mmiotrace_rw(struct trace_array *tr, } entry = ring_buffer_event_data(event); entry->rw = *rw; - trace_buffer_unlock_commit(tr, event, 0, pc); + trace_buffer_unlock_commit(buffer, event, 0, pc); } void mmio_trace_rw(struct mmiotrace_rw *rw) @@ -333,11 +334,12 @@ static void __trace_mmiotrace_map(struct trace_array *tr, struct trace_array_cpu *data, struct mmiotrace_map *map) { + struct ring_buffer *buffer = tr->buffer; struct ring_buffer_event *event; struct trace_mmiotrace_map *entry; int pc = preempt_count(); - event = trace_buffer_lock_reserve(tr, TRACE_MMIO_MAP, + event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP, sizeof(*entry), 0, pc); if (!event) { atomic_inc(&dropped_count); @@ -345,7 +347,7 @@ static void __trace_mmiotrace_map(struct trace_array *tr, } entry = ring_buffer_event_data(event); entry->map = *map; - trace_buffer_unlock_commit(tr, event, 0, pc); + trace_buffer_unlock_commit(buffer, event, 0, pc); } void mmio_trace_mapping(struct mmiotrace_map *map) diff --git a/kernel/trace/trace_power.c b/kernel/trace/trace_power.c index a5d5a4f..fe1a00f 100644 --- a/kernel/trace/trace_power.c +++ b/kernel/trace/trace_power.c @@ -38,6 +38,7 @@ static void probe_power_end(struct power_trace *it) { struct ftrace_event_call *call = &event_power; struct ring_buffer_event *event; + struct ring_buffer *buffer; struct trace_power *entry; struct trace_array_cpu *data; struct trace_array *tr = power_trace; @@ -45,18 +46,20 @@ static void probe_power_end(struct power_trace *it) if (!trace_power_enabled) return; + buffer = tr->buffer; + preempt_disable(); it->end = ktime_get(); data = tr->data[smp_processor_id()]; - event = trace_buffer_lock_reserve(tr, TRACE_POWER, + event = trace_buffer_lock_reserve(buffer, TRACE_POWER, sizeof(*entry), 0, 0); if (!event) goto out; entry = ring_buffer_event_data(event); entry->state_data = *it; - if (!filter_check_discard(call, entry, tr->buffer, event)) - trace_buffer_unlock_commit(tr, event, 0, 0); + if (!filter_check_discard(call, entry, buffer, event)) + trace_buffer_unlock_commit(buffer, event, 0, 0); out: preempt_enable(); } @@ -66,6 +69,7 @@ static void probe_power_mark(struct power_trace *it, unsigned int type, { struct ftrace_event_call *call = &event_power; struct ring_buffer_event *event; + struct ring_buffer *buffer; struct trace_power *entry; struct trace_array_cpu *data; struct trace_array *tr = power_trace; @@ -73,6 +77,8 @@ static void probe_power_mark(struct power_trace *it, unsigned int type, if (!trace_power_enabled) return; + buffer = tr->buffer; + memset(it, 0, sizeof(struct power_trace)); it->state = level; it->type = type; @@ -81,14 +87,14 @@ static void probe_power_mark(struct power_trace *it, unsigned int type, it->end = it->stamp; data = tr->data[smp_processor_id()]; - event = trace_buffer_lock_reserve(tr, TRACE_POWER, + event = trace_buffer_lock_reserve(buffer, TRACE_POWER, sizeof(*entry), 0, 0); if (!event) goto out; entry = ring_buffer_event_data(event); entry->state_data = *it; - if (!filter_check_discard(call, entry, tr->buffer, event)) - trace_buffer_unlock_commit(tr, event, 0, 0); + if (!filter_check_discard(call, entry, buffer, event)) + trace_buffer_unlock_commit(buffer, event, 0, 0); out: preempt_enable(); } diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index e1285d7..5fca0f5 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -28,10 +28,11 @@ tracing_sched_switch_trace(struct trace_array *tr, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_context_switch; + struct ring_buffer *buffer = tr->buffer; struct ring_buffer_event *event; struct ctx_switch_entry *entry; - event = trace_buffer_lock_reserve(tr, TRACE_CTX, + event = trace_buffer_lock_reserve(buffer, TRACE_CTX, sizeof(*entry), flags, pc); if (!event) return; @@ -44,8 +45,8 @@ tracing_sched_switch_trace(struct trace_array *tr, entry->next_state = next->state; entry->next_cpu = task_cpu(next); - if (!filter_check_discard(call, entry, tr->buffer, event)) - trace_buffer_unlock_commit(tr, event, flags, pc); + if (!filter_check_discard(call, entry, buffer, event)) + trace_buffer_unlock_commit(buffer, event, flags, pc); } static void @@ -86,8 +87,9 @@ tracing_sched_wakeup_trace(struct trace_array *tr, struct ftrace_event_call *call = &event_wakeup; struct ring_buffer_event *event; struct ctx_switch_entry *entry; + struct ring_buffer *buffer = tr->buffer; - event = trace_buffer_lock_reserve(tr, TRACE_WAKE, + event = trace_buffer_lock_reserve(buffer, TRACE_WAKE, sizeof(*entry), flags, pc); if (!event) return; @@ -100,10 +102,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr, entry->next_state = wakee->state; entry->next_cpu = task_cpu(wakee); - if (!filter_check_discard(call, entry, tr->buffer, event)) - ring_buffer_unlock_commit(tr->buffer, event); - ftrace_trace_stack(tr, flags, 6, pc); - ftrace_trace_userstack(tr, flags, pc); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); + ftrace_trace_stack(tr->buffer, flags, 6, pc); + ftrace_trace_userstack(tr->buffer, flags, pc); } static void diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 4f5fae6..8712ce3 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -223,6 +223,7 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id) struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; + struct ring_buffer *buffer; int size; int syscall_nr; @@ -238,8 +239,8 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id) size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args; - event = trace_current_buffer_lock_reserve(sys_data->enter_id, size, - 0, 0); + event = trace_current_buffer_lock_reserve(&buffer, sys_data->enter_id, + size, 0, 0); if (!event) return; @@ -247,8 +248,9 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id) entry->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); - if (!filter_current_check_discard(sys_data->enter_event, entry, event)) - trace_current_buffer_unlock_commit(event, 0, 0); + if (!filter_current_check_discard(buffer, sys_data->enter_event, + entry, event)) + trace_current_buffer_unlock_commit(buffer, event, 0, 0); } void ftrace_syscall_exit(struct pt_regs *regs, long ret) @@ -256,6 +258,7 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret) struct syscall_trace_exit *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; + struct ring_buffer *buffer; int syscall_nr; syscall_nr = syscall_get_nr(current, regs); @@ -268,7 +271,7 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret) if (!sys_data) return; - event = trace_current_buffer_lock_reserve(sys_data->exit_id, + event = trace_current_buffer_lock_reserve(&buffer, sys_data->exit_id, sizeof(*entry), 0, 0); if (!event) return; @@ -277,8 +280,9 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret) entry->nr = syscall_nr; entry->ret = syscall_get_return_value(current, regs); - if (!filter_current_check_discard(sys_data->exit_event, entry, event)) - trace_current_buffer_unlock_commit(event, 0, 0); + if (!filter_current_check_discard(buffer, sys_data->exit_event, + entry, event)) + trace_current_buffer_unlock_commit(buffer, event, 0, 0); } int reg_event_syscall_enter(void *ptr) -- cgit v1.1 From 659372d3e42a3e17a2e042d38a8bcdb94bfbe797 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 19:11:07 -0400 Subject: tracing: add trace_array_printk for internal tracers to use This patch adds a trace_array_printk to allow a tracer to use the trace_printk on its own trace array. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 24 ++++++++++++++++++++++-- kernel/trace/trace.h | 5 +++++ 2 files changed, 27 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0c61836..ef08328 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1201,7 +1201,23 @@ out: } EXPORT_SYMBOL_GPL(trace_vbprintk); -int trace_vprintk(unsigned long ip, const char *fmt, va_list args) +int trace_array_printk(struct trace_array *tr, + unsigned long ip, const char *fmt, ...) +{ + int ret; + va_list ap; + + if (!(trace_flags & TRACE_ITER_PRINTK)) + return 0; + + va_start(ap, fmt); + ret = trace_array_vprintk(tr, ip, fmt, ap); + va_end(ap); + return ret; +} + +int trace_array_vprintk(struct trace_array *tr, + unsigned long ip, const char *fmt, va_list args) { static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED; static char trace_buf[TRACE_BUF_SIZE]; @@ -1209,7 +1225,6 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) struct ftrace_event_call *call = &event_print; struct ring_buffer_event *event; struct ring_buffer *buffer; - struct trace_array *tr = &global_trace; struct trace_array_cpu *data; int cpu, len = 0, size, pc; struct print_entry *entry; @@ -1260,6 +1275,11 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) return len; } + +int trace_vprintk(unsigned long ip, const char *fmt, va_list args) +{ + return trace_array_printk(&global_trace, ip, fmt, args); +} EXPORT_SYMBOL_GPL(trace_vprintk); enum trace_file_type { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4d30414..fa1dccb 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -566,6 +566,11 @@ extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args); extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args); +extern int +trace_array_vprintk(struct trace_array *tr, + unsigned long ip, const char *fmt, va_list args); +int trace_array_printk(struct trace_array *tr, + unsigned long ip, const char *fmt, ...); extern unsigned long trace_flags; -- cgit v1.1 From e8165dbb03ed04d798163ee512074b9a9466a9c8 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 19:13:05 -0400 Subject: tracing: report error in trace if we fail to swap latency buffer The irqsoff tracer will fail to swap the cpu buffer with the max buffer if it preempts a commit. Instead of ignoring this, this patch makes the tracer report it if the last max latency failed due to preempting a current commit. The output of the latency tracer will look like this: # tracer: irqsoff # # irqsoff latency trace v1.1.5 on 2.6.31-rc5 # -------------------------------------------------------------------- # latency: 112 us, #1/1, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -4281 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # => started at: save_args # => ended at: __do_softirq # # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / bash-4281 1d.s6 265us : update_max_tr_single: Failed to swap buffers due to commit in progress Note the latency time and the functions that disabled the irqs or preemption will still be listed. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ef08328..6df9861 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -482,9 +482,20 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu); + if (ret == -EBUSY) { + /* + * We failed to swap the buffer due to a commit taking + * place on this CPU. We fail to record, but we reset + * the max trace buffer (no one writes directly to it) + * and flag that it failed. + */ + trace_array_printk(&max_tr, _THIS_IP_, + "Failed to swap buffers due to commit in progress\n"); + } + ftrace_enable_cpu(); - WARN_ON_ONCE(ret && ret != -EAGAIN); + WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); __update_max_tr(tr, tsk, cpu); __raw_spin_unlock(&ftrace_max_lock); -- cgit v1.1 From 62f0b3eb5cb58931a02ee4e599e19c80a171e351 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 4 Sep 2009 14:11:34 -0400 Subject: ring-buffer: check for swapped buffers in start of committing Because the irqsoff tracer can swap an internal CPU buffer, it is possible that a swap happens between the start of the write and before the committing bit is set (the committing bit will disable swapping). This patch adds a check for this and will fail the write if it detects it. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index f83a42a..1766c0e 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2073,7 +2073,8 @@ static void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer) } static struct ring_buffer_event * -rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer, +rb_reserve_next_event(struct ring_buffer *buffer, + struct ring_buffer_per_cpu *cpu_buffer, unsigned long length) { struct ring_buffer_event *event; @@ -2083,6 +2084,19 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer, rb_start_commit(cpu_buffer); + /* + * Due to the ability to swap a cpu buffer from a buffer + * it is possible it was swapped before we committed. + * (committing stops a swap). We check for it here and + * if it happened, we have to fail the write. + */ + barrier(); + if (unlikely(ACCESS_ONCE(cpu_buffer->buffer) != buffer)) { + local_dec(&cpu_buffer->committing); + local_dec(&cpu_buffer->commits); + return NULL; + } + length = rb_calculate_event_length(length); again: /* @@ -2243,7 +2257,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length) if (length > BUF_MAX_DATA_SIZE) goto out; - event = rb_reserve_next_event(cpu_buffer, length); + event = rb_reserve_next_event(buffer, cpu_buffer, length); if (!event) goto out; @@ -2476,7 +2490,7 @@ int ring_buffer_write(struct ring_buffer *buffer, if (length > BUF_MAX_DATA_SIZE) goto out; - event = rb_reserve_next_event(cpu_buffer, length); + event = rb_reserve_next_event(buffer, cpu_buffer, length); if (!event) goto out; -- cgit v1.1 From 85bac32c4a52c592b857f2c360cc5ec93a097d70 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 4 Sep 2009 14:24:40 -0400 Subject: ring-buffer: only enable ring_buffer_swap_cpu when needed Since the ability to swap the cpu buffers adds a small overhead to the recording of a trace, we only want to add it when needed. Only the irqsoff and preemptoff tracers use this feature, and both are not recommended for production kernels. This patch disables its use when neither irqsoff nor preemptoff is configured. Signed-off-by: Steven Rostedt --- kernel/trace/Kconfig | 8 ++++++++ kernel/trace/ring_buffer.c | 4 ++++ 2 files changed, 12 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 163fbfc..1ea0d12 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -62,6 +62,12 @@ config EVENT_TRACING config CONTEXT_SWITCH_TRACER bool +config RING_BUFFER_ALLOW_SWAP + bool + help + Allow the use of ring_buffer_swap_cpu. + Adds a very slight overhead to tracing when enabled. + # All tracer options should select GENERIC_TRACER. For those options that are # enabled by all tracers (context switch and event tracer) they select TRACING. # This allows those options to appear when no other tracer is selected. But the @@ -146,6 +152,7 @@ config IRQSOFF_TRACER select TRACE_IRQFLAGS select GENERIC_TRACER select TRACER_MAX_TRACE + select RING_BUFFER_ALLOW_SWAP help This option measures the time spent in irqs-off critical sections, with microsecond accuracy. @@ -167,6 +174,7 @@ config PREEMPT_TRACER depends on PREEMPT select GENERIC_TRACER select TRACER_MAX_TRACE + select RING_BUFFER_ALLOW_SWAP help This option measures the time spent in preemption off critical sections, with microsecond accuracy. diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1766c0e..454e74e 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2084,6 +2084,7 @@ rb_reserve_next_event(struct ring_buffer *buffer, rb_start_commit(cpu_buffer); +#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP /* * Due to the ability to swap a cpu buffer from a buffer * it is possible it was swapped before we committed. @@ -2096,6 +2097,7 @@ rb_reserve_next_event(struct ring_buffer *buffer, local_dec(&cpu_buffer->commits); return NULL; } +#endif length = rb_calculate_event_length(length); again: @@ -3498,6 +3500,7 @@ int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu) } EXPORT_SYMBOL_GPL(ring_buffer_empty_cpu); +#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP /** * ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers * @buffer_a: One buffer to swap with @@ -3573,6 +3576,7 @@ out: return ret; } EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu); +#endif /* CONFIG_RING_BUFFER_ALLOW_SWAP */ /** * ring_buffer_alloc_read_page - allocate a page to read from buffer -- cgit v1.1