From: tip-bot for Konstantin Khlebnikov <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, hpa@zytor.com,
khlebnikov@yandex-team.ru, bsegall@google.com,
peterz@infradead.org, torvalds@linux-foundation.org,
tglx@linutronix.de
Subject: [tip:sched/urgent] sched/fair: Do not announce throttled next buddy in dequeue_task_fair()
Date: Fri, 24 Jun 2016 02:00:03 -0700 [thread overview]
Message-ID: <tip-754bd598be9bbc953bc709a9e8ed7f3188bfb9d7@git.kernel.org> (raw)
In-Reply-To: <146608183552.21905.15924473394414832071.stgit@buzz>
Commit-ID: 754bd598be9bbc953bc709a9e8ed7f3188bfb9d7
Gitweb: http://git.kernel.org/tip/754bd598be9bbc953bc709a9e8ed7f3188bfb9d7
Author: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
AuthorDate: Thu, 16 Jun 2016 15:57:15 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 24 Jun 2016 08:26:45 +0200
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>
---
kernel/sched/fair.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8c5d8c0..bdcbeea 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;
next prev parent reply other threads:[~2016-06-24 9:00 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 12:57 [PATCH] sched/fair: do not announce throttled next buddy in dequeue_task_fair Konstantin Khlebnikov
2016-06-16 17:06 ` bsegall
2016-06-21 13:44 ` Konstantin Khlebnikov
2016-06-24 9:00 ` tip-bot for Konstantin Khlebnikov [this message]
2016-07-11 7:25 ` Wanpeng Li
2016-07-11 8:15 ` Konstantin Khlebnikov
2016-07-11 8:22 ` Xunlei Pang
2016-07-11 8:42 ` Xunlei Pang
2016-07-11 9:54 ` Wanpeng Li
2016-07-11 12:12 ` Xunlei Pang
2016-07-11 12:26 ` Konstantin Khlebnikov
2016-07-12 17:25 ` bsegall
2016-07-13 1:50 ` Wanpeng Li
2016-07-13 1:58 ` Xunlei Pang
2016-07-13 2:14 ` Wanpeng Li
2016-07-13 17:06 ` bsegall
2016-07-14 12:11 ` Wanpeng Li
2016-07-14 17:54 ` bsegall
2016-07-14 22:30 ` Wanpeng Li
2016-07-14 22:49 ` bsegall
2016-07-14 23:03 ` Wanpeng Li
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