Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core

12 files changed, 98 insertions, 39 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index d9d5648f3cd..a184470cf9b 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2098,11 +2098,6 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
 			continue;
 		/* get old css_set pointer */
 		task_lock(tsk);
-		if (tsk->flags & PF_EXITING) {
-			/* ignore this task if it's going away */
-			task_unlock(tsk);
-			continue;
-		}
 		oldcg = tsk->cgroups;
 		get_css_set(oldcg);
 		task_unlock(tsk);
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 9fe58c46a42..0b1712dba58 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -123,6 +123,19 @@ static inline struct cpuset *task_cs(struct task_struct *task)
 			    struct cpuset, css);
 }
 
+#ifdef CONFIG_NUMA
+static inline bool task_has_mempolicy(struct task_struct *task)
+{
+	return task->mempolicy;
+}
+#else
+static inline bool task_has_mempolicy(struct task_struct *task)
+{
+	return false;
+}
+#endif
+
+
 /* bits in struct cpuset flags field */
 typedef enum {
 	CS_CPU_EXCLUSIVE,
@@ -949,7 +962,7 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
 static void cpuset_change_task_nodemask(struct task_struct *tsk,
 					nodemask_t *newmems)
 {
-	bool masks_disjoint = !nodes_intersects(*newmems, tsk->mems_allowed);
+	bool need_loop;
 
 repeat:
 	/*
@@ -962,6 +975,14 @@ repeat:
 		return;
 
 	task_lock(tsk);
+	/*
+	 * Determine if a loop is necessary if another thread is doing
+	 * get_mems_allowed().  If at least one node remains unchanged and
+	 * tsk does not have a mempolicy, then an empty nodemask will not be
+	 * possible when mems_allowed is larger than a word.
+	 */
+	need_loop = task_has_mempolicy(tsk) ||
+			!nodes_intersects(*newmems, tsk->mems_allowed);
 	nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
 	mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
 
@@ -981,11 +1002,9 @@ repeat:
 
 	/*
 	 * Allocation of memory is very fast, we needn't sleep when waiting
-	 * for the read-side.  No wait is necessary, however, if at least one
-	 * node remains unchanged.
+	 * for the read-side.
 	 */
-	while (masks_disjoint &&
-			ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
+	while (need_loop && ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
 		task_unlock(tsk);
 		if (!task_curr(tsk))
 			yield();
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2f8f3f103cb..24e3a4b1c89 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3360,9 +3360,13 @@ static void ring_buffer_wakeup(struct perf_event *event)
 
 	rcu_read_lock();
 	rb = rcu_dereference(event->rb);
-	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
+	if (!rb)
+		goto unlock;
+
+	list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
 		wake_up_all(&event->waitq);
-	}
+
+unlock:
 	rcu_read_unlock();
 }
 
diff --git a/kernel/exit.c b/kernel/exit.c
index d0b7d988f87..e6e01b959a0 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1540,8 +1540,15 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
 	}
 
 	/* dead body doesn't have much to contribute */
-	if (p->exit_state == EXIT_DEAD)
+	if (unlikely(p->exit_state == EXIT_DEAD)) {
+		/*
+		 * But do not ignore this task until the tracer does
+		 * wait_task_zombie()->do_notify_parent().
+		 */
+		if (likely(!ptrace) && unlikely(ptrace_reparented(p)))
+			wo->notask_error = 0;
 		return 0;
+	}
 
 	/* slay zombie? */
 	if (p->exit_state == EXIT_ZOMBIE) {
diff --git a/kernel/futex.c b/kernel/futex.c
index ea87f4d2f45..1614be20173 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -314,17 +314,29 @@ again:
 #endif
 
 	lock_page(page_head);
+
+	/*
+	 * If page_head->mapping is NULL, then it cannot be a PageAnon
+	 * page; but it might be the ZERO_PAGE or in the gate area or
+	 * in a special mapping (all cases which we are happy to fail);
+	 * or it may have been a good file page when get_user_pages_fast
+	 * found it, but truncated or holepunched or subjected to
+	 * invalidate_complete_page2 before we got the page lock (also
+	 * cases which we are happy to fail).  And we hold a reference,
+	 * so refcount care in invalidate_complete_page's remove_mapping
+	 * prevents drop_caches from setting mapping to NULL beneath us.
+	 *
+	 * The case we do have to guard against is when memory pressure made
+	 * shmem_writepage move it from filecache to swapcache beneath us:
+	 * an unlikely race, but we do need to retry for page_head->mapping.
+	 */
 	if (!page_head->mapping) {
+		int shmem_swizzled = PageSwapCache(page_head);
 		unlock_page(page_head);
 		put_page(page_head);
-		/*
-		* ZERO_PAGE pages don't have a mapping. Avoid a busy loop
-		* trying to find one. RW mapping would have COW'd (and thus
-		* have a mapping) so this page is RO and won't ever change.
-		*/
-		if ((page_head == ZERO_PAGE(address)))
-			return -EFAULT;
-		goto again;
+		if (shmem_swizzled)
+			goto again;
+		return -EFAULT;
 	}
 
 	/*
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 8b1748d0172..2e48ec0c2e9 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -74,11 +74,17 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 
 	/*
 	 * Ensure the task is not frozen.
-	 * Also, when a freshly created task is scheduled once, changes
-	 * its state to TASK_UNINTERRUPTIBLE without having ever been
-	 * switched out once, it musn't be checked.
+	 * Also, skip vfork and any other user process that freezer should skip.
 	 */
-	if (unlikely(t->flags & PF_FROZEN || !switch_count))
+	if (unlikely(t->flags & (PF_FROZEN | PF_FREEZER_SKIP)))
+	    return;
+
+	/*
+	 * When a freshly created task is scheduled once, changes its state to
+	 * TASK_UNINTERRUPTIBLE without having ever been switched out once, it
+	 * musn't be checked.
+	 */
+	if (unlikely(!switch_count))
 		return;
 
 	if (switch_count != t->last_switch_count) {
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 24d04477b25..78ab24a7b0e 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -96,9 +96,20 @@ void __ptrace_unlink(struct task_struct *child)
 	 */
 	if (!(child->flags & PF_EXITING) &&
 	    (child->signal->flags & SIGNAL_STOP_STOPPED ||
-	     child->signal->group_stop_count))
+	     child->signal->group_stop_count)) {
 		child->jobctl |= JOBCTL_STOP_PENDING;
 
+		/*
+		 * This is only possible if this thread was cloned by the
+		 * traced task running in the stopped group, set the signal
+		 * for the future reports.
+		 * FIXME: we should change ptrace_init_task() to handle this
+		 * case.
+		 */
+		if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
+			child->jobctl |= SIGSTOP;
+	}
+
 	/*
 	 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
 	 * @child in the butt.  Note that @resume should be used iff @child
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a78ed2736ba..8a39fa3e3c6 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -2352,13 +2352,11 @@ again:
 		if (!smt && (sd->flags & SD_SHARE_CPUPOWER))
 			continue;
 
-		if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) {
-			if (!smt) {
-				smt = 1;
-				goto again;
-			}
+		if (smt && !(sd->flags & SD_SHARE_CPUPOWER))
+			break;
+
+		if (!(sd->flags & SD_SHARE_PKG_RESOURCES))
 			break;
-		}
 
 		sg = sd->groups;
 		do {
@@ -2378,6 +2376,10 @@ next:
 			sg = sg->next;
 		} while (sg != sd->groups);
 	}
+	if (!smt) {
+		smt = 1;
+		goto again;
+	}
 done:
 	rcu_read_unlock();
 
diff --git a/kernel/signal.c b/kernel/signal.c
index b3f78d09a10..206551563cc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1994,8 +1994,6 @@ static bool do_signal_stop(int signr)
 		 */
 		if (!(sig->flags & SIGNAL_STOP_STOPPED))
 			sig->group_exit_code = signr;
-		else
-			WARN_ON_ONCE(!current->ptrace);
 
 		sig->group_stop_count = 0;
 
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 6318b511afa..a650694883a 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1354,7 +1354,7 @@ static ssize_t binary_sysctl(const int *name, int nlen,
 
 	fput(file);
 out_putname:
-	putname(pathname);
+	__putname(pathname);
 out:
 	return result;
 }
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index c4eb71c8b2e..1ecd6ba36d6 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -387,7 +387,6 @@ void clockevents_exchange_device(struct clock_event_device *old,
 	 * released list and do a notify add later.
 	 */
 	if (old) {
-		old->event_handler = clockevents_handle_noop;
 		clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
 		list_del(&old->list);
 		list_add(&old->list, &clockevents_released);
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index da2f760e780..d3ad022136e 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -647,7 +647,7 @@ static void clocksource_enqueue(struct clocksource *cs)
 
 /**
  * __clocksource_updatefreq_scale - Used update clocksource with new freq
- * @t:		clocksource to be registered
+ * @cs:		clocksource to be registered
  * @scale:	Scale factor multiplied against freq to get clocksource hz
  * @freq:	clocksource frequency (cycles per second) divided by scale
  *
@@ -699,7 +699,7 @@ EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale);
 
 /**
  * __clocksource_register_scale - Used to install new clocksources
- * @t:		clocksource to be registered
+ * @cs:		clocksource to be registered
  * @scale:	Scale factor multiplied against freq to get clocksource hz
  * @freq:	clocksource frequency (cycles per second) divided by scale
  *
@@ -727,7 +727,7 @@ EXPORT_SYMBOL_GPL(__clocksource_register_scale);
 
 /**
  * clocksource_register - Used to install new clocksources
- * @t:		clocksource to be registered
+ * @cs:		clocksource to be registered
  *
  * Returns -EBUSY if registration fails, zero otherwise.
  */
@@ -761,6 +761,8 @@ static void __clocksource_change_rating(struct clocksource *cs, int rating)
 
 /**
  * clocksource_change_rating - Change the rating of a registered clocksource
+ * @cs:		clocksource to be changed
+ * @rating:	new rating
  */
 void clocksource_change_rating(struct clocksource *cs, int rating)
 {
@@ -772,6 +774,7 @@ EXPORT_SYMBOL(clocksource_change_rating);
 
 /**
  * clocksource_unregister - remove a registered clocksource
+ * @cs:	clocksource to be unregistered
  */
 void clocksource_unregister(struct clocksource *cs)
 {
@@ -787,6 +790,7 @@ EXPORT_SYMBOL(clocksource_unregister);
 /**
  * sysfs_show_current_clocksources - sysfs interface for current clocksource
  * @dev:	unused
+ * @attr:	unused
  * @buf:	char buffer to be filled with clocksource list
  *
  * Provides sysfs interface for listing current clocksource.
@@ -807,6 +811,7 @@ sysfs_show_current_clocksources(struct sys_device *dev,
 /**
  * sysfs_override_clocksource - interface for manually overriding clocksource
  * @dev:	unused
+ * @attr:	unused
  * @buf:	name of override clocksource
  * @count:	length of buffer
  *
@@ -842,6 +847,7 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
 /**
  * sysfs_show_available_clocksources - sysfs interface for listing clocksource
  * @dev:	unused
+ * @attr:	unused
  * @buf:	char buffer to be filled with clocksource list
  *
  * Provides sysfs interface for listing registered clocksources