[GIT PULL] scheduler fix

[Ingo Molnar]

Linus,

Please pull the latest sched-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 
sched-urgent-for-linus

   # HEAD: e3d85487fba42206024bc3ed32e4b581c7cb46db sched/core: Fix preempt 
warning in ttwu

Fix a sched statistics related bug that would trigger a kernel warning on 
certain configs.

 Thanks,

        Ingo

------------------>
Peter Zijlstra (1):
      sched/core: Fix preempt warning in ttwu


 kernel/sched/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fa43ce3962e7..2b037f195473 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2399,6 +2399,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, 
int wake_flags)
        unsigned long flags;
        int cpu, success = 0;
 
+       preempt_disable();
        if (p == current) {
                /*
                 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
@@ -2412,7 +2413,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, 
int wake_flags)
                 *    it disabling IRQs (this allows not taking ->pi_lock).
                 */
                if (!(p->state & state))
-                       return false;
+                       goto out;
 
                success = 1;
                cpu = task_cpu(p);
@@ -2526,6 +2527,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, 
int wake_flags)
 out:
        if (success)
                ttwu_stat(p, cpu, wake_flags);
+       preempt_enable();
 
        return success;
 }