summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2016-06-16 15:57:15 +0300
committerIngo Molnar <mingo@kernel.org>2016-06-24 08:26:45 +0200
commit754bd598be9bbc953bc709a9e8ed7f3188bfb9d7 (patch)
treecfb67972d70b0bcb1f3eccb042a5b8f8e432d045
parent094f469172e00d6ab0a3130b0e01c83b3cf3a98d (diff)
downloadlinux-754bd598be9bbc953bc709a9e8ed7f3188bfb9d7.tar.gz
sched/fair: Do not announce throttled next buddy in dequeue_task_fair()
Hierarchy could be already throttled at this point. Throttled next buddy could trigger a NULL pointer dereference in pick_next_task_fair(). Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/146608183552.21905.15924473394414832071.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/fair.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8c5d8c0c8827..bdcbeea90c95 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4537,15 +4537,14 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
/* Don't dequeue parent if it has other entities besides us */
if (cfs_rq->load.weight) {
+ /* Avoid re-evaluating load for this entity: */
+ se = parent_entity(se);
/*
* Bias pick_next to pick a task from this cfs_rq, as
* p is sleeping when it is within its sched_slice.
*/
- if (task_sleep && parent_entity(se))
- set_next_buddy(parent_entity(se));
-
- /* avoid re-evaluating load for this entity */
- se = parent_entity(se);
+ if (task_sleep && se && !throttled_hierarchy(cfs_rq))
+ set_next_buddy(se);
break;
}
flags |= DEQUEUE_SLEEP;