diff options
Diffstat (limited to 'kernel/trace/trace_events.c')
-rw-r--r-- | kernel/trace/trace_events.c | 506 |
1 files changed, 479 insertions, 27 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 7ca09cd..6bbc5f6 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -15,11 +15,15 @@ #include <linux/kthread.h> #include <linux/tracefs.h> #include <linux/uaccess.h> +#include <linux/bsearch.h> #include <linux/module.h> #include <linux/ctype.h> +#include <linux/sort.h> #include <linux/slab.h> #include <linux/delay.h> +#include <trace/events/sched.h> + #include <asm/setup.h> #include "trace_output.h" @@ -38,21 +42,19 @@ static LIST_HEAD(ftrace_common_fields); static struct kmem_cache *field_cachep; static struct kmem_cache *file_cachep; -#define SYSTEM_FL_FREE_NAME (1 << 31) - static inline int system_refcount(struct event_subsystem *system) { - return system->ref_count & ~SYSTEM_FL_FREE_NAME; + return system->ref_count; } static int system_refcount_inc(struct event_subsystem *system) { - return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME; + return system->ref_count++; } static int system_refcount_dec(struct event_subsystem *system) { - return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME; + return --system->ref_count; } /* Double loops, do not use break, only goto's work */ @@ -212,12 +214,32 @@ int trace_event_raw_init(struct trace_event_call *call) } EXPORT_SYMBOL_GPL(trace_event_raw_init); +bool trace_event_ignore_this_pid(struct trace_event_file *trace_file) +{ + struct trace_array *tr = trace_file->tr; + struct trace_array_cpu *data; + struct trace_pid_list *pid_list; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + if (!pid_list) + return false; + + data = this_cpu_ptr(tr->trace_buffer.data); + + return data->ignore_pid; +} +EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid); + void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer, struct trace_event_file *trace_file, unsigned long len) { struct trace_event_call *event_call = trace_file->event_call; + if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) && + trace_event_ignore_this_pid(trace_file)) + return NULL; + local_save_flags(fbuffer->flags); fbuffer->pc = preempt_count(); fbuffer->trace_file = trace_file; @@ -338,6 +360,7 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file, int enable, int soft_disable) { struct trace_event_call *call = file->event_call; + struct trace_array *tr = file->tr; int ret = 0; int disable; @@ -401,7 +424,7 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file, if (soft_disable) set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags); - if (trace_flags & TRACE_ITER_RECORD_CMD) { + if (tr->trace_flags & TRACE_ITER_RECORD_CMD) { tracing_start_cmdline_record(); set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags); } @@ -446,6 +469,142 @@ static void ftrace_clear_events(struct trace_array *tr) mutex_unlock(&event_mutex); } +static int cmp_pid(const void *key, const void *elt) +{ + const pid_t *search_pid = key; + const pid_t *pid = elt; + + if (*search_pid == *pid) + return 0; + if (*search_pid < *pid) + return -1; + return 1; +} + +static bool +check_ignore_pid(struct trace_pid_list *filtered_pids, struct task_struct *task) +{ + pid_t search_pid; + pid_t *pid; + + /* + * Return false, because if filtered_pids does not exist, + * all pids are good to trace. + */ + if (!filtered_pids) + return false; + + search_pid = task->pid; + + pid = bsearch(&search_pid, filtered_pids->pids, + filtered_pids->nr_pids, sizeof(pid_t), + cmp_pid); + if (!pid) + return true; + + return false; +} + +static void +event_filter_pid_sched_switch_probe_pre(void *data, bool preempt, + struct task_struct *prev, struct task_struct *next) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, prev) && + check_ignore_pid(pid_list, next)); +} + +static void +event_filter_pid_sched_switch_probe_post(void *data, bool preempt, + struct task_struct *prev, struct task_struct *next) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, next)); +} + +static void +event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + /* Nothing to do if we are already tracing */ + if (!this_cpu_read(tr->trace_buffer.data->ignore_pid)) + return; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, task)); +} + +static void +event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + /* Nothing to do if we are not tracing */ + if (this_cpu_read(tr->trace_buffer.data->ignore_pid)) + return; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + /* Set tracing if current is enabled */ + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, current)); +} + +static void __ftrace_clear_event_pids(struct trace_array *tr) +{ + struct trace_pid_list *pid_list; + struct trace_event_file *file; + int cpu; + + pid_list = rcu_dereference_protected(tr->filtered_pids, + lockdep_is_held(&event_mutex)); + if (!pid_list) + return; + + unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr); + unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr); + + unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr); + unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr); + + list_for_each_entry(file, &tr->events, list) { + clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags); + } + + for_each_possible_cpu(cpu) + per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false; + + rcu_assign_pointer(tr->filtered_pids, NULL); + + /* Wait till all users are no longer using pid filtering */ + synchronize_sched(); + + free_pages((unsigned long)pid_list->pids, pid_list->order); + kfree(pid_list); +} + +static void ftrace_clear_event_pids(struct trace_array *tr) +{ + mutex_lock(&event_mutex); + __ftrace_clear_event_pids(tr); + mutex_unlock(&event_mutex); +} + static void __put_system(struct event_subsystem *system) { struct event_filter *filter = system->filter; @@ -460,8 +619,7 @@ static void __put_system(struct event_subsystem *system) kfree(filter->filter_string); kfree(filter); } - if (system->ref_count & SYSTEM_FL_FREE_NAME) - kfree(system->name); + kfree_const(system->name); kfree(system); } @@ -779,6 +937,58 @@ static void t_stop(struct seq_file *m, void *p) mutex_unlock(&event_mutex); } +static void *p_start(struct seq_file *m, loff_t *pos) + __acquires(RCU) +{ + struct trace_pid_list *pid_list; + struct trace_array *tr = m->private; + + /* + * Grab the mutex, to keep calls to p_next() having the same + * tr->filtered_pids as p_start() has. + * If we just passed the tr->filtered_pids around, then RCU would + * have been enough, but doing that makes things more complex. + */ + mutex_lock(&event_mutex); + rcu_read_lock_sched(); + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + if (!pid_list || *pos >= pid_list->nr_pids) + return NULL; + + return (void *)&pid_list->pids[*pos]; +} + +static void p_stop(struct seq_file *m, void *p) + __releases(RCU) +{ + rcu_read_unlock_sched(); + mutex_unlock(&event_mutex); +} + +static void * +p_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct trace_array *tr = m->private; + struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids); + + (*pos)++; + + if (*pos >= pid_list->nr_pids) + return NULL; + + return (void *)&pid_list->pids[*pos]; +} + +static int p_show(struct seq_file *m, void *v) +{ + pid_t *pid = v; + + seq_printf(m, "%d\n", *pid); + return 0; +} + static ssize_t event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) @@ -1336,8 +1546,209 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) return r; } +static int max_pids(struct trace_pid_list *pid_list) +{ + return (PAGE_SIZE << pid_list->order) / sizeof(pid_t); +} + +static void ignore_task_cpu(void *data) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + /* + * This function is called by on_each_cpu() while the + * event_mutex is held. + */ + pid_list = rcu_dereference_protected(tr->filtered_pids, + mutex_is_locked(&event_mutex)); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, current)); +} + +static ssize_t +ftrace_event_pid_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct seq_file *m = filp->private_data; + struct trace_array *tr = m->private; + struct trace_pid_list *filtered_pids = NULL; + struct trace_pid_list *pid_list = NULL; + struct trace_event_file *file; + struct trace_parser parser; + unsigned long val; + loff_t this_pos; + ssize_t read = 0; + ssize_t ret = 0; + pid_t pid; + int i; + + if (!cnt) + return 0; + + ret = tracing_update_buffers(); + if (ret < 0) + return ret; + + if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1)) + return -ENOMEM; + + mutex_lock(&event_mutex); + /* + * Load as many pids into the array before doing a + * swap from the tr->filtered_pids to the new list. + */ + while (cnt > 0) { + + this_pos = 0; + + ret = trace_get_user(&parser, ubuf, cnt, &this_pos); + if (ret < 0 || !trace_parser_loaded(&parser)) + break; + + read += ret; + ubuf += ret; + cnt -= ret; + + parser.buffer[parser.idx] = 0; + + ret = -EINVAL; + if (kstrtoul(parser.buffer, 0, &val)) + break; + if (val > INT_MAX) + break; + + pid = (pid_t)val; + + ret = -ENOMEM; + if (!pid_list) { + pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL); + if (!pid_list) + break; + + filtered_pids = rcu_dereference_protected(tr->filtered_pids, + lockdep_is_held(&event_mutex)); + if (filtered_pids) + pid_list->order = filtered_pids->order; + else + pid_list->order = 0; + + pid_list->pids = (void *)__get_free_pages(GFP_KERNEL, + pid_list->order); + if (!pid_list->pids) + break; + + if (filtered_pids) { + pid_list->nr_pids = filtered_pids->nr_pids; + memcpy(pid_list->pids, filtered_pids->pids, + pid_list->nr_pids * sizeof(pid_t)); + } else + pid_list->nr_pids = 0; + } + + if (pid_list->nr_pids >= max_pids(pid_list)) { + pid_t *pid_page; + + pid_page = (void *)__get_free_pages(GFP_KERNEL, + pid_list->order + 1); + if (!pid_page) + break; + memcpy(pid_page, pid_list->pids, + pid_list->nr_pids * sizeof(pid_t)); + free_pages((unsigned long)pid_list->pids, pid_list->order); + + pid_list->order++; + pid_list->pids = pid_page; + } + + pid_list->pids[pid_list->nr_pids++] = pid; + trace_parser_clear(&parser); + ret = 0; + } + trace_parser_put(&parser); + + if (ret < 0) { + if (pid_list) + free_pages((unsigned long)pid_list->pids, pid_list->order); + kfree(pid_list); + mutex_unlock(&event_mutex); + return ret; + } + + if (!pid_list) { + mutex_unlock(&event_mutex); + return ret; + } + + sort(pid_list->pids, pid_list->nr_pids, sizeof(pid_t), cmp_pid, NULL); + + /* Remove duplicates */ + for (i = 1; i < pid_list->nr_pids; i++) { + int start = i; + + while (i < pid_list->nr_pids && + pid_list->pids[i - 1] == pid_list->pids[i]) + i++; + + if (start != i) { + if (i < pid_list->nr_pids) { + memmove(&pid_list->pids[start], &pid_list->pids[i], + (pid_list->nr_pids - i) * sizeof(pid_t)); + pid_list->nr_pids -= i - start; + i = start; + } else + pid_list->nr_pids = start; + } + } + + rcu_assign_pointer(tr->filtered_pids, pid_list); + + list_for_each_entry(file, &tr->events, list) { + set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags); + } + + if (filtered_pids) { + synchronize_sched(); + + free_pages((unsigned long)filtered_pids->pids, filtered_pids->order); + kfree(filtered_pids); + } else { + /* + * Register a probe that is called before all other probes + * to set ignore_pid if next or prev do not match. + * Register a probe this is called after all other probes + * to only keep ignore_pid set if next pid matches. + */ + register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre, + tr, INT_MAX); + register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post, + tr, 0); + + register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, + tr, INT_MAX); + register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, + tr, 0); + } + + /* + * Ignoring of pids is done at task switch. But we have to + * check for those tasks that are currently running. + * Always do this in case a pid was appended or removed. + */ + on_each_cpu(ignore_task_cpu, tr, 1); + + mutex_unlock(&event_mutex); + + ret = read; + *ppos += read; + + return ret; +} + static int ftrace_event_avail_open(struct inode *inode, struct file *file); static int ftrace_event_set_open(struct inode *inode, struct file *file); +static int ftrace_event_set_pid_open(struct inode *inode, struct file *file); static int ftrace_event_release(struct inode *inode, struct file *file); static const struct seq_operations show_event_seq_ops = { @@ -1354,6 +1765,13 @@ static const struct seq_operations show_set_event_seq_ops = { .stop = t_stop, }; +static const struct seq_operations show_set_pid_seq_ops = { + .start = p_start, + .next = p_next, + .show = p_show, + .stop = p_stop, +}; + static const struct file_operations ftrace_avail_fops = { .open = ftrace_event_avail_open, .read = seq_read, @@ -1369,6 +1787,14 @@ static const struct file_operations ftrace_set_event_fops = { .release = ftrace_event_release, }; +static const struct file_operations ftrace_set_event_pid_fops = { + .open = ftrace_event_set_pid_open, + .read = seq_read, + .write = ftrace_event_pid_write, + .llseek = seq_lseek, + .release = ftrace_event_release, +}; + static const struct file_operations ftrace_enable_fops = { .open = tracing_open_generic, .read = event_enable_read, @@ -1479,6 +1905,26 @@ ftrace_event_set_open(struct inode *inode, struct file *file) return ret; } +static int +ftrace_event_set_pid_open(struct inode *inode, struct file *file) +{ + const struct seq_operations *seq_ops = &show_set_pid_seq_ops; + struct trace_array *tr = inode->i_private; + int ret; + + if (trace_array_get(tr) < 0) + return -ENODEV; + + if ((file->f_mode & FMODE_WRITE) && + (file->f_flags & O_TRUNC)) + ftrace_clear_event_pids(tr); + + ret = ftrace_event_open(inode, file, seq_ops); + if (ret < 0) + trace_array_put(tr); + return ret; +} + static struct event_subsystem * create_new_subsystem(const char *name) { @@ -1492,13 +1938,9 @@ create_new_subsystem(const char *name) system->ref_count = 1; /* Only allocate if dynamic (kprobes and modules) */ - if (!core_kernel_data((unsigned long)name)) { - system->ref_count |= SYSTEM_FL_FREE_NAME; - system->name = kstrdup(name, GFP_KERNEL); - if (!system->name) - goto out_free; - } else - system->name = name; + system->name = kstrdup_const(name, GFP_KERNEL); + if (!system->name) + goto out_free; system->filter = NULL; @@ -1511,8 +1953,7 @@ create_new_subsystem(const char *name) return system; out_free: - if (system->ref_count & SYSTEM_FL_FREE_NAME) - kfree(system->name); + kfree_const(system->name); kfree(system); return NULL; } @@ -2478,6 +2919,9 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) return -ENOMEM; } + entry = tracefs_create_file("set_event_pid", 0644, parent, + tr, &ftrace_set_event_pid_fops); + /* ring buffer internal formats */ trace_create_file("header_page", 0444, d_events, ring_buffer_print_page_header, @@ -2558,6 +3002,9 @@ int event_trace_del_tracer(struct trace_array *tr) /* Disable any event triggers and associated soft-disabled events */ clear_event_triggers(tr); + /* Clear the pid list */ + __ftrace_clear_event_pids(tr); + /* Disable any running events */ __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0); @@ -2595,16 +3042,16 @@ early_enable_events(struct trace_array *tr, bool disable_first) if (!token) break; - if (!*token) - continue; - /* Restarting syscalls requires that we stop them first */ - if (disable_first) - ftrace_set_clr_event(tr, token, 0); + if (*token) { + /* Restarting syscalls requires that we stop them first */ + if (disable_first) + ftrace_set_clr_event(tr, token, 0); - ret = ftrace_set_clr_event(tr, token, 1); - if (ret) - pr_warn("Failed to enable trace event: %s\n", token); + ret = ftrace_set_clr_event(tr, token, 1); + if (ret) + pr_warn("Failed to enable trace event: %s\n", token); + } /* Put back the comma to allow this to be called again */ if (buf) @@ -2891,7 +3338,9 @@ static __init void event_trace_self_tests(void) static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable); -static void +static struct trace_array *event_tr; + +static void __init function_test_events_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *pt_regs) { @@ -2922,7 +3371,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip, entry->ip = ip; entry->parent_ip = parent_ip; - trace_buffer_unlock_commit(buffer, event, flags, pc); + trace_buffer_unlock_commit(event_tr, buffer, event, flags, pc); out: atomic_dec(&per_cpu(ftrace_test_event_disable, cpu)); @@ -2938,6 +3387,9 @@ static struct ftrace_ops trace_ops __initdata = static __init void event_trace_self_test_with_function(void) { int ret; + event_tr = top_trace_array(); + if (WARN_ON(!event_tr)) + return; ret = register_ftrace_function(&trace_ops); if (WARN_ON(ret < 0)) { pr_info("Failed to enable function tracer for event tests\n"); |