19 files changed, 286 insertions, 118 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 9a3ec66..19fad00 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -11,8 +11,6 @@ obj-y     = sched.o fork.o exec_domain.o panic.o printk.o \
 	    hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
 	    notifier.o ksysfs.o pm_qos_params.o sched_clock.o
 
-CFLAGS_REMOVE_sched.o = -mno-spe
-
 ifdef CONFIG_FUNCTION_TRACER
 # Do not trace debug files and internal ftrace files
 CFLAGS_REMOVE_lockdep.o = -pg
@@ -21,7 +19,7 @@ CFLAGS_REMOVE_mutex-debug.o = -pg
 CFLAGS_REMOVE_rtmutex-debug.o = -pg
 CFLAGS_REMOVE_cgroup-debug.o = -pg
 CFLAGS_REMOVE_sched_clock.o = -pg
-CFLAGS_REMOVE_sched.o = -mno-spe -pg
+CFLAGS_REMOVE_sched.o = -pg
 endif
 
 obj-$(CONFIG_FREEZER) += freezer.o
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 8ba0e0d..8b50944 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -24,6 +24,7 @@ struct audit_chunk {
 	struct list_head trees;		/* with root here */
 	int dead;
 	int count;
+	atomic_long_t refs;
 	struct rcu_head head;
 	struct node {
 		struct list_head list;
@@ -56,7 +57,8 @@ static LIST_HEAD(prune_list);
  * tree is refcounted; one reference for "some rules on rules_list refer to
  * it", one for each chunk with pointer to it.
  *
- * chunk is refcounted by embedded inotify_watch.
+ * chunk is refcounted by embedded inotify_watch + .refs (non-zero refcount
+ * of watch contributes 1 to .refs).
  *
  * node.index allows to get from node.list to containing chunk.
  * MSB of that sucker is stolen to mark taggings that we might have to
@@ -121,6 +123,7 @@ static struct audit_chunk *alloc_chunk(int count)
 	INIT_LIST_HEAD(&chunk->hash);
 	INIT_LIST_HEAD(&chunk->trees);
 	chunk->count = count;
+	atomic_long_set(&chunk->refs, 1);
 	for (i = 0; i < count; i++) {
 		INIT_LIST_HEAD(&chunk->owners[i].list);
 		chunk->owners[i].index = i;
@@ -129,9 +132,8 @@ static struct audit_chunk *alloc_chunk(int count)
 	return chunk;
 }
 
-static void __free_chunk(struct rcu_head *rcu)
+static void free_chunk(struct audit_chunk *chunk)
 {
-	struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
 	int i;
 
 	for (i = 0; i < chunk->count; i++) {
@@ -141,14 +143,16 @@ static void __free_chunk(struct rcu_head *rcu)
 	kfree(chunk);
 }
 
-static inline void free_chunk(struct audit_chunk *chunk)
+void audit_put_chunk(struct audit_chunk *chunk)
 {
-	call_rcu(&chunk->head, __free_chunk);
+	if (atomic_long_dec_and_test(&chunk->refs))
+		free_chunk(chunk);
 }
 
-void audit_put_chunk(struct audit_chunk *chunk)
+static void __put_chunk(struct rcu_head *rcu)
 {
-	put_inotify_watch(&chunk->watch);
+	struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
+	audit_put_chunk(chunk);
 }
 
 enum {HASH_SIZE = 128};
@@ -176,7 +180,7 @@ struct audit_chunk *audit_tree_lookup(const struct inode *inode)
 
 	list_for_each_entry_rcu(p, list, hash) {
 		if (p->watch.inode == inode) {
-			get_inotify_watch(&p->watch);
+			atomic_long_inc(&p->refs);
 			return p;
 		}
 	}
@@ -194,17 +198,49 @@ int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
 
 /* tagging and untagging inodes with trees */
 
-static void untag_chunk(struct audit_chunk *chunk, struct node *p)
+static struct audit_chunk *find_chunk(struct node *p)
+{
+	int index = p->index & ~(1U<<31);
+	p -= index;
+	return container_of(p, struct audit_chunk, owners[0]);
+}
+
+static void untag_chunk(struct node *p)
 {
+	struct audit_chunk *chunk = find_chunk(p);
 	struct audit_chunk *new;
 	struct audit_tree *owner;
 	int size = chunk->count - 1;
 	int i, j;
 
+	if (!pin_inotify_watch(&chunk->watch)) {
+		/*
+		 * Filesystem is shutting down; all watches are getting
+		 * evicted, just take it off the node list for this
+		 * tree and let the eviction logics take care of the
+		 * rest.
+		 */
+		owner = p->owner;
+		if (owner->root == chunk) {
+			list_del_init(&owner->same_root);
+			owner->root = NULL;
+		}
+		list_del_init(&p->list);
+		p->owner = NULL;
+		put_tree(owner);
+		return;
+	}
+
+	spin_unlock(&hash_lock);
+
+	/*
+	 * pin_inotify_watch() succeeded, so the watch won't go away
+	 * from under us.
+	 */
 	mutex_lock(&chunk->watch.inode->inotify_mutex);
 	if (chunk->dead) {
 		mutex_unlock(&chunk->watch.inode->inotify_mutex);
-		return;
+		goto out;
 	}
 
 	owner = p->owner;
@@ -221,7 +257,7 @@ static void untag_chunk(struct audit_chunk *chunk, struct node *p)
 		inotify_evict_watch(&chunk->watch);
 		mutex_unlock(&chunk->watch.inode->inotify_mutex);
 		put_inotify_watch(&chunk->watch);
-		return;
+		goto out;
 	}
 
 	new = alloc_chunk(size);
@@ -263,7 +299,7 @@ static void untag_chunk(struct audit_chunk *chunk, struct node *p)
 	inotify_evict_watch(&chunk->watch);
 	mutex_unlock(&chunk->watch.inode->inotify_mutex);
 	put_inotify_watch(&chunk->watch);
-	return;
+	goto out;
 
 Fallback:
 	// do the best we can
@@ -277,6 +313,9 @@ Fallback:
 	put_tree(owner);
 	spin_unlock(&hash_lock);
 	mutex_unlock(&chunk->watch.inode->inotify_mutex);
+out:
+	unpin_inotify_watch(&chunk->watch);
+	spin_lock(&hash_lock);
 }
 
 static int create_chunk(struct inode *inode, struct audit_tree *tree)
@@ -387,13 +426,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
 	return 0;
 }
 
-static struct audit_chunk *find_chunk(struct node *p)
-{
-	int index = p->index & ~(1U<<31);
-	p -= index;
-	return container_of(p, struct audit_chunk, owners[0]);
-}
-
 static void kill_rules(struct audit_tree *tree)
 {
 	struct audit_krule *rule, *next;
@@ -431,17 +463,10 @@ static void prune_one(struct audit_tree *victim)
 	spin_lock(&hash_lock);
 	while (!list_empty(&victim->chunks)) {
 		struct node *p;
-		struct audit_chunk *chunk;
 
 		p = list_entry(victim->chunks.next, struct node, list);
-		chunk = find_chunk(p);
-		get_inotify_watch(&chunk->watch);
-		spin_unlock(&hash_lock);
-
-		untag_chunk(chunk, p);
 
-		put_inotify_watch(&chunk->watch);
-		spin_lock(&hash_lock);
+		untag_chunk(p);
 	}
 	spin_unlock(&hash_lock);
 	put_tree(victim);
@@ -469,7 +494,6 @@ static void trim_marked(struct audit_tree *tree)
 
 	while (!list_empty(&tree->chunks)) {
 		struct node *node;
-		struct audit_chunk *chunk;
 
 		node = list_entry(tree->chunks.next, struct node, list);
 
@@ -477,14 +501,7 @@ static void trim_marked(struct audit_tree *tree)
 		if (!(node->index & (1U<<31)))
 			break;
 
-		chunk = find_chunk(node);
-		get_inotify_watch(&chunk->watch);
-		spin_unlock(&hash_lock);
-
-		untag_chunk(chunk, node);
-
-		put_inotify_watch(&chunk->watch);
-		spin_lock(&hash_lock);
+		untag_chunk(node);
 	}
 	if (!tree->root && !tree->goner) {
 		tree->goner = 1;
@@ -878,7 +895,7 @@ static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
 static void destroy_watch(struct inotify_watch *watch)
 {
 	struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
-	free_chunk(chunk);
+	call_rcu(&chunk->head, __put_chunk);
 }
 
 static const struct inotify_operations rtree_inotify_ops = {
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index b7d354e..9fd85a4 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1094,8 +1094,8 @@ static void audit_inotify_unregister(struct list_head *in_list)
 	list_for_each_entry_safe(p, n, in_list, ilist) {
 		list_del(&p->ilist);
 		inotify_rm_watch(audit_ih, &p->wdata);
-		/* the put matching the get in audit_do_del_rule() */
-		put_inotify_watch(&p->wdata);
+		/* the unpin matching the pin in audit_do_del_rule() */
+		unpin_inotify_watch(&p->wdata);
 	}
 }
 
@@ -1389,9 +1389,13 @@ static inline int audit_del_rule(struct audit_entry *entry,
 				/* Put parent on the inotify un-registration
 				 * list.  Grab a reference before releasing
 				 * audit_filter_mutex, to be released in
-				 * audit_inotify_unregister(). */
-				list_add(&parent->ilist, &inotify_list);
-				get_inotify_watch(&parent->wdata);
+				 * audit_inotify_unregister().
+				 * If filesystem is going away, just leave
+				 * the sucker alone, eviction will take
+				 * care of it.
+				 */
+				if (pin_inotify_watch(&parent->wdata))
+					list_add(&parent->ilist, &inotify_list);
 			}
 		}
 	}
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 7fa476f..fb249e2 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -184,9 +184,20 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
 {
 	struct freezer *freezer;
 
-	task_lock(task);
+	/*
+	 * No lock is needed, since the task isn't on tasklist yet,
+	 * so it can't be moved to another cgroup, which means the
+	 * freezer won't be removed and will be valid during this
+	 * function call.
+	 */
 	freezer = task_freezer(task);
-	task_unlock(task);
+
+	/*
+	 * The root cgroup is non-freezable, so we can skip the
+	 * following check.
+	 */
+	if (!freezer->css.cgroup->parent)
+		return;
 
 	spin_lock_irq(&freezer->lock);
 	BUG_ON(freezer->state == CGROUP_FROZEN);
@@ -331,7 +342,7 @@ static int freezer_write(struct cgroup *cgroup,
 	else if (strcmp(buffer, freezer_state_strs[CGROUP_FROZEN]) == 0)
 		goal_state = CGROUP_FROZEN;
 	else
-		return -EIO;
+		return -EINVAL;
 
 	if (!cgroup_lock_live_group(cgroup))
 		return -ENODEV;
@@ -350,6 +361,8 @@ static struct cftype files[] = {
 
 static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
 {
+	if (!cgroup->parent)
+		return 0;
 	return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files));
 }
 
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3e00526..81fc679 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -587,7 +587,6 @@ static int generate_sched_domains(cpumask_t **domains,
 	int ndoms;		/* number of sched domains in result */
 	int nslot;		/* next empty doms[] cpumask_t slot */
 
-	ndoms = 0;
 	doms = NULL;
 	dattr = NULL;
 	csa = NULL;
@@ -674,10 +673,8 @@ restart:
 	 * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
 	 */
 	doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
-	if (!doms) {
-		ndoms = 0;
+	if (!doms)
 		goto done;
-	}
 
 	/*
 	 * The rest of the code, including the scheduler, can deal with
@@ -732,6 +729,13 @@ restart:
 done:
 	kfree(csa);
 
+	/*
+	 * Fallback to the default domain if kmalloc() failed.
+	 * See comments in partition_sched_domains().
+	 */
+	if (doms == NULL)
+		ndoms = 1;
+
 	*domains    = doms;
 	*attributes = dattr;
 	return ndoms;
diff --git a/kernel/exit.c b/kernel/exit.c
index ae2b92b..2d8be7e 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -40,7 +40,6 @@
 #include <linux/cn_proc.h>
 #include <linux/mutex.h>
 #include <linux/futex.h>
-#include <linux/compat.h>
 #include <linux/pipe_fs_i.h>
 #include <linux/audit.h> /* for audit_free() */
 #include <linux/resource.h>
@@ -1059,14 +1058,6 @@ NORET_TYPE void do_exit(long code)
 		exit_itimers(tsk->signal);
 	}
 	acct_collect(code, group_dead);
-#ifdef CONFIG_FUTEX
-	if (unlikely(tsk->robust_list))
-		exit_robust_list(tsk);
-#ifdef CONFIG_COMPAT
-	if (unlikely(tsk->compat_robust_list))
-		compat_exit_robust_list(tsk);
-#endif
-#endif
 	if (group_dead)
 		tty_audit_exit();
 	if (unlikely(tsk->audit_context))
diff --git a/kernel/fork.c b/kernel/fork.c
index f608356..2a372a0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -40,6 +40,7 @@
 #include <linux/jiffies.h>
 #include <linux/tracehook.h>
 #include <linux/futex.h>
+#include <linux/compat.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/rcupdate.h>
 #include <linux/ptrace.h>
@@ -519,6 +520,16 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
 	struct completion *vfork_done = tsk->vfork_done;
 
+	/* Get rid of any futexes when releasing the mm */
+#ifdef CONFIG_FUTEX
+	if (unlikely(tsk->robust_list))
+		exit_robust_list(tsk);
+#ifdef CONFIG_COMPAT
+	if (unlikely(tsk->compat_robust_list))
+		compat_exit_robust_list(tsk);
+#endif
+#endif
+
 	/* Get rid of any cached register state */
 	deactivate_mm(tsk, mm);
 
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 95d3949..47e6334 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -664,14 +664,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
 
 		/* Timer is expired, act upon the callback mode */
 		switch(timer->cb_mode) {
-		case HRTIMER_CB_IRQSAFE_NO_RESTART:
-			debug_hrtimer_deactivate(timer);
-			/*
-			 * We can call the callback from here. No restart
-			 * happens, so no danger of recursion
-			 */
-			BUG_ON(timer->function(timer) != HRTIMER_NORESTART);
-			return 1;
 		case HRTIMER_CB_IRQSAFE_PERCPU:
 		case HRTIMER_CB_IRQSAFE_UNLOCKED:
 			/*
@@ -683,7 +675,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
 			 */
 			debug_hrtimer_deactivate(timer);
 			return 1;
-		case HRTIMER_CB_IRQSAFE:
 		case HRTIMER_CB_SOFTIRQ:
 			/*
 			 * Move everything else into the softirq pending list !
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8b57a25..9f8a3f2 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -72,7 +72,7 @@ static bool kprobe_enabled;
 DEFINE_MUTEX(kprobe_mutex);		/* Protects kprobe_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 static struct {
-	spinlock_t lock ____cacheline_aligned;
+	spinlock_t lock ____cacheline_aligned_in_smp;
 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
 
 static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
@@ -613,30 +613,37 @@ static int __kprobes __register_kprobe(struct kprobe *p,
 		return -EINVAL;
 	p->addr = addr;
 
-	if (!kernel_text_address((unsigned long) p->addr) ||
-	    in_kprobes_functions((unsigned long) p->addr))
+	preempt_disable();
+	if (!__kernel_text_address((unsigned long) p->addr) ||
+	    in_kprobes_functions((unsigned long) p->addr)) {
+		preempt_enable();
 		return -EINVAL;
+	}
 
 	p->mod_refcounted = 0;
 
 	/*
 	 * Check if are we probing a module.
 	 */
-	probed_mod = module_text_address((unsigned long) p->addr);
+	probed_mod = __module_text_address((unsigned long) p->addr);
 	if (probed_mod) {
-		struct module *calling_mod = module_text_address(called_from);
+		struct module *calling_mod;
+		calling_mod = __module_text_address(called_from);
 		/*
 		 * We must allow modules to probe themself and in this case
 		 * avoid incrementing the module refcount, so as to allow
 		 * unloading of self probing modules.
 		 */
 		if (calling_mod && calling_mod != probed_mod) {
-			if (unlikely(!try_module_get(probed_mod)))
+			if (unlikely(!try_module_get(probed_mod))) {
+				preempt_enable();
 				return -EINVAL;
+			}
 			p->mod_refcounted = 1;
 		} else
 			probed_mod = NULL;
 	}
+	preempt_enable();
 
 	p->nmissed = 0;
 	INIT_LIST_HEAD(&p->list);
@@ -718,6 +725,10 @@ static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
 	struct kprobe *old_p;
 
 	if (p->mod_refcounted) {
+		/*
+		 * Since we've already incremented refcount,
+		 * we don't need to disable preemption.
+		 */
 		mod = module_text_address((unsigned long)p->addr);
 		if (mod)
 			module_put(mod);
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 153dcb2..895337b 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1308,9 +1308,10 @@ static inline int task_cputime_expired(const struct task_cputime *sample,
  */
 static inline int fastpath_timer_check(struct task_struct *tsk)
 {
-	struct signal_struct *sig = tsk->signal;
+	struct signal_struct *sig;
 
-	if (unlikely(!sig))
+	/* tsk == current, ensure it is safe to use ->signal/sighand */
+	if (unlikely(tsk->exit_state))
 		return 0;
 
 	if (!task_cputime_zero(&tsk->cputime_expires)) {
@@ -1323,6 +1324,8 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 		if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
 			return 1;
 	}
+
+	sig = tsk->signal;
 	if (!task_cputime_zero(&sig->cputime_expires)) {
 		struct task_cputime group_sample;
 
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 19122cf..b8f7ce9 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -174,7 +174,7 @@ static void suspend_test_finish(const char *label)
 	 * has some performance issues.  The stack dump of a WARN_ON
 	 * is more likely to get the right attention than a printk...
 	 */
-	WARN_ON(msec > (TEST_SUSPEND_SECONDS * 1000));
+	WARN(msec > (TEST_SUSPEND_SECONDS * 1000), "Component: %s\n", label);
 }
 
 #else
diff --git a/kernel/profile.c b/kernel/profile.c
index 9830a03..5b7d1ac 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -544,7 +544,7 @@ static const struct file_operations proc_profile_operations = {
 };
 
 #ifdef CONFIG_SMP
-static void __init profile_nop(void *unused)
+static inline void profile_nop(void *unused)
 {
 }
 
diff --git a/kernel/relay.c b/kernel/relay.c
index 8d13a78..32b0bef 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -400,7 +400,7 @@ void relay_reset(struct rchan *chan)
 	}
 
 	mutex_lock(&relay_channels_mutex);
-	for_each_online_cpu(i)
+	for_each_possible_cpu(i)
 		if (chan->buf[i])
 			__relay_reset(chan->buf[i], 0);
 	mutex_unlock(&relay_channels_mutex);
@@ -611,10 +611,9 @@ struct rchan *relay_open(const char *base_filename,
 	return chan;
 
 free_bufs:
-	for_each_online_cpu(i) {
-		if (!chan->buf[i])
-			break;
-		relay_close_buf(chan->buf[i]);
+	for_each_possible_cpu(i) {
+		if (chan->buf[i])
+			relay_close_buf(chan->buf[i]);
 	}
 
 	kref_put(&chan->kref, relay_destroy_channel);
diff --git a/kernel/sched.c b/kernel/sched.c
index 50a21f9..9b1e793 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1456,6 +1456,8 @@ static unsigned long cpu_avg_load_per_task(int cpu)
 
 	if (rq->nr_running)
 		rq->avg_load_per_task = rq->load.weight / rq->nr_running;
+	else
+		rq->avg_load_per_task = 0;
 
 	return rq->avg_load_per_task;
 }
@@ -5868,6 +5870,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
 	struct rq *rq = cpu_rq(cpu);
 	unsigned long flags;
 
+	spin_lock_irqsave(&rq->lock, flags);
+
 	__sched_fork(idle);
 	idle->se.exec_start = sched_clock();
 
@@ -5875,7 +5879,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
 	idle->cpus_allowed = cpumask_of_cpu(cpu);
 	__set_task_cpu(idle, cpu);
 
-	spin_lock_irqsave(&rq->lock, flags);
 	rq->curr = rq->idle = idle;
 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
 	idle->oncpu = 1;
@@ -7786,13 +7789,14 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
  *
  * The passed in 'doms_new' should be kmalloc'd. This routine takes
  * ownership of it and will kfree it when done with it. If the caller
- * failed the kmalloc call, then it can pass in doms_new == NULL,
- * and partition_sched_domains() will fallback to the single partition
- * 'fallback_doms', it also forces the domains to be rebuilt.
+ * failed the kmalloc call, then it can pass in doms_new == NULL &&
+ * ndoms_new == 1, and partition_sched_domains() will fallback to
+ * the single partition 'fallback_doms', it also forces the domains
+ * to be rebuilt.
  *
- * If doms_new==NULL it will be replaced with cpu_online_map.
- * ndoms_new==0 is a special case for destroying existing domains.
- * It will not create the default domain.
+ * If doms_new == NULL it will be replaced with cpu_online_map.
+ * ndoms_new == 0 is a special case for destroying existing domains,
+ * and it will not create the default domain.
  *
  * Call with hotplug lock held
  */
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 48ecc51..26ed8e3 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -423,10 +423,11 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
 #undef __P
 
 	{
+		unsigned int this_cpu = raw_smp_processor_id();
 		u64 t0, t1;
 
-		t0 = sched_clock();
-		t1 = sched_clock();
+		t0 = cpu_clock(this_cpu);
+		t1 = cpu_clock(this_cpu);
 		SEQ_printf(m, "%-35s:%21Ld\n",
 			   "clock-delta", (long long)(t1-t0));
 	}
diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h
index ee71bec..7dbf72a 100644
--- a/kernel/sched_stats.h
+++ b/kernel/sched_stats.h
@@ -298,9 +298,11 @@ static inline void account_group_user_time(struct task_struct *tsk,
 {
 	struct signal_struct *sig;
 
-	sig = tsk->signal;
-	if (unlikely(!sig))
+	/* tsk == current, ensure it is safe to use ->signal */
+	if (unlikely(tsk->exit_state))
 		return;
+
+	sig = tsk->signal;
 	if (sig->cputime.totals) {
 		struct task_cputime *times;
 
@@ -325,9 +327,11 @@ static inline void account_group_system_time(struct task_struct *tsk,
 {
 	struct signal_struct *sig;
 
-	sig = tsk->signal;
-	if (unlikely(!sig))
+	/* tsk == current, ensure it is safe to use ->signal */
+	if (unlikely(tsk->exit_state))
 		return;
+
+	sig = tsk->signal;
 	if (sig->cputime.totals) {
 		struct task_cputime *times;
 
@@ -353,8 +357,11 @@ static inline void account_group_exec_runtime(struct task_struct *tsk,
 	struct signal_struct *sig;
 
 	sig = tsk->signal;
+	/* see __exit_signal()->task_rq_unlock_wait() */
+	barrier();
 	if (unlikely(!sig))
 		return;
+
 	if (sig->cputime.totals) {
 		struct task_cputime *times;
 
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 9bc4c00..24e8cea 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -112,7 +112,7 @@ static int chill(void *unused)
 int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
 {
 	struct work_struct *sm_work;
-	int i;
+	int i, ret;
 
 	/* Set up initial state. */
 	mutex_lock(&lock);
@@ -137,8 +137,9 @@ int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
 	/* This will release the thread on our CPU. */
 	put_cpu();
 	flush_workqueue(stop_machine_wq);
+	ret = active.fnret;
 	mutex_unlock(&lock);
-	return active.fnret;
+	return ret;
 }
 
 int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4a39d24..e602057 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -185,7 +185,6 @@ enum {
 };
 
 static int ftrace_filtered;
-static int tracing_on;
 
 static LIST_HEAD(ftrace_new_addrs);
 
@@ -506,13 +505,10 @@ static int __ftrace_modify_code(void *data)
 {
 	int *command = data;
 
-	if (*command & FTRACE_ENABLE_CALLS) {
+	if (*command & FTRACE_ENABLE_CALLS)
 		ftrace_replace_code(1);
-		tracing_on = 1;
-	} else if (*command & FTRACE_DISABLE_CALLS) {
+	else if (*command & FTRACE_DISABLE_CALLS)
 		ftrace_replace_code(0);
-		tracing_on = 0;
-	}
 
 	if (*command & FTRACE_UPDATE_TRACE_FUNC)
 		ftrace_update_ftrace_func(ftrace_trace_function);
@@ -677,7 +673,7 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 
 	cnt = num_to_init / ENTRIES_PER_PAGE;
 	pr_info("ftrace: allocating %ld entries in %d pages\n",
-		num_to_init, cnt);
+		num_to_init, cnt + 1);
 
 	for (i = 0; i < cnt; i++) {
 		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -757,13 +753,11 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 	void *p = NULL;
 	loff_t l = -1;
 
-	if (*pos != iter->pos) {
-		for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
-			;
-	} else {
-		l = *pos;
-		p = t_next(m, p, &l);
-	}
+	if (*pos > iter->pos)
+		*pos = iter->pos;
+
+	l = *pos;
+	p = t_next(m, p, &l);
 
 	return p;
 }
@@ -774,15 +768,21 @@ static void t_stop(struct seq_file *m, void *p)
 
 static int t_show(struct seq_file *m, void *v)
 {
+	struct ftrace_iterator *iter = m->private;
 	struct dyn_ftrace *rec = v;
 	char str[KSYM_SYMBOL_LEN];
+	int ret = 0;
 
 	if (!rec)
 		return 0;
 
 	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 
-	seq_printf(m, "%s\n", str);
+	ret = seq_printf(m, "%s\n", str);
+	if (ret < 0) {
+		iter->pos--;
+		iter->idx--;
+	}
 
 	return 0;
 }
@@ -808,7 +808,7 @@ ftrace_avail_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 
 	iter->pg = ftrace_pages_start;
-	iter->pos = -1;
+	iter->pos = 0;
 
 	ret = seq_open(file, &show_ftrace_seq_ops);
 	if (!ret) {
@@ -895,7 +895,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
 	if (file->f_mode & FMODE_READ) {
 		iter->pg = ftrace_pages_start;
-		iter->pos = -1;
+		iter->pos = 0;
 		iter->flags = enable ? FTRACE_ITER_FILTER :
 			FTRACE_ITER_NOTRACE;
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2f76193..036456c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -16,14 +16,49 @@
 #include <linux/list.h>
 #include <linux/fs.h>
 
+#include "trace.h"
+
+/* Global flag to disable all recording to ring buffers */
+static int ring_buffers_off __read_mostly;
+
+/**
+ * tracing_on - enable all tracing buffers
+ *
+ * This function enables all tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+	ring_buffers_off = 0;
+}
+
+/**
+ * tracing_off - turn off all tracing buffers
+ *
+ * This function stops all tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+	ring_buffers_off = 1;
+}
+
 /* Up this if you want to test the TIME_EXTENTS and normalization */
 #define DEBUG_SHIFT 0
 
 /* FIXME!!! */
 u64 ring_buffer_time_stamp(int cpu)
 {
+	u64 time;
+
+	preempt_disable_notrace();
 	/* shift to debug/test normalization and TIME_EXTENTS */
-	return sched_clock() << DEBUG_SHIFT;
+	time = sched_clock() << DEBUG_SHIFT;
+	preempt_enable_notrace();
+
+	return time;
 }
 
 void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
@@ -503,6 +538,12 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
 	LIST_HEAD(pages);
 	int i, cpu;
 
+	/*
+	 * Always succeed at resizing a non-existent buffer:
+	 */
+	if (!buffer)
+		return size;
+
 	size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
 	size *= BUF_PAGE_SIZE;
 	buffer_size = buffer->pages * BUF_PAGE_SIZE;
@@ -1133,6 +1174,9 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer,
 	struct ring_buffer_event *event;
 	int cpu, resched;
 
+	if (ring_buffers_off)
+		return NULL;
+
 	if (atomic_read(&buffer->record_disabled))
 		return NULL;
 
@@ -1249,6 +1293,9 @@ int ring_buffer_write(struct ring_buffer *buffer,
 	int ret = -EBUSY;
 	int cpu, resched;
 
+	if (ring_buffers_off)
+		return -EBUSY;
+
 	if (atomic_read(&buffer->record_disabled))
 		return -EBUSY;
 
@@ -2070,3 +2117,69 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
 	return 0;
 }
 
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+	       size_t cnt, loff_t *ppos)
+{
+	int *p = filp->private_data;
+	char buf[64];
+	int r;
+
+	/* !ring_buffers_off == tracing_on */
+	r = sprintf(buf, "%d\n", !*p);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos)
+{
+	int *p = filp->private_data;
+	char buf[64];
+	long val;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	/* !ring_buffers_off == tracing_on */
+	*p = !val;
+
+	(*ppos)++;
+
+	return cnt;
+}
+
+static struct file_operations rb_simple_fops = {
+	.open		= tracing_open_generic,
+	.read		= rb_simple_read,
+	.write		= rb_simple_write,
+};
+
+
+static __init int rb_init_debugfs(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+
+	entry = debugfs_create_file("tracing_on", 0644, d_tracer,
+				    &ring_buffers_off, &rb_simple_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'tracing_on' entry\n");
+
+	return 0;
+}
+
+fs_initcall(rb_init_debugfs);