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| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2016-06-16 15:57:15 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-24 08:26:45 +0200 |
| commit | 754bd598be9bbc953bc709a9e8ed7f3188bfb9d7 (patch) | |
| tree | cfb67972d70b0bcb1f3eccb042a5b8f8e432d045 /kernel/sched | |
| parent | 094f469172e00d6ab0a3130b0e01c83b3cf3a98d (diff) | |
| download | lwn-754bd598be9bbc953bc709a9e8ed7f3188bfb9d7.tar.gz lwn-754bd598be9bbc953bc709a9e8ed7f3188bfb9d7.zip | |
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>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 9 |
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; |