The commit is pushed to "branch-rh7-3.10.0-229.7.2-ovz" and will appear at
https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.6.7
------>
commit e0e09e8e04e11319568ed71e13214a7d4e5810c7
Author: Vladimir Davydov <[email protected]>
Date: Mon Sep 7 14:15:46 2015 +0400
sched/fair: only update current task boost
put_prev_task, which calls update_entity_boost, may be invoked for prev
!= current (e.g. on setprio). In rare cases (e.g. cpu offline), this is
done before dequeue_task. As a result, a task might not get removed from
the list of boosted entity on dequeue, leading to a crash.
Anyway, it only makes sense to call update_entity_boost on current task,
because it relies on preempt_count and flips task_struct bit fields. So
insert the appropriate check to this function in order to fix this
issue.
Reported-by: Kirill Tkhai <[email protected]>
Signed-off-by: Vladimir Davydov <[email protected]>
Acked-by: Kirill Tkhai <[email protected]>
---
kernel/sched/fair.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3092f763f767..171601d766f8 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -960,6 +960,9 @@ static inline void update_entity_boost(struct sched_entity
*se)
else {
struct task_struct *p = task_of(se);
+ if (unlikely(p != current))
+ return;
+
if (!(preempt_count() & PREEMPT_ACTIVE)) {
se->boosted = sched_feat(BOOST_WAKEUPS) &&
p->woken_while_running;
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