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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-07-30 12:13:56 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-07-30 12:13:56 -0700 |
commit | ae3e10aba57c284818fd493b18732ce8a4632e1e (patch) | |
tree | a9a7b4ee6eda59f7da79f1fe882f81618b5e6300 /kernel/stop_machine.c | |
parent | 0634922a78f08df22037ec4ddee717f92d892a68 (diff) | |
parent | f3d133ee0a17d5694c6f21873eec9863e11fa423 (diff) |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Misc fixes:
- a deadline scheduler related bug fix which triggered a kernel
warning
- an RT_RUNTIME_SHARE fix
- a stop_machine preemption fix
- a potential NULL dereference fix in sched_domain_debug_one()"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/rt: Restore rt_runtime after disabling RT_RUNTIME_SHARE
sched/deadline: Update rq_clock of later_rq when pushing a task
stop_machine: Disable preemption after queueing stopper threads
sched/topology: Check variable group before dereferencing it
Diffstat (limited to 'kernel/stop_machine.c')
-rw-r--r-- | kernel/stop_machine.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 1ff523dae6e2..e190d1ef3a23 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -260,6 +260,15 @@ retry: err = 0; __cpu_stop_queue_work(stopper1, work1, &wakeq); __cpu_stop_queue_work(stopper2, work2, &wakeq); + /* + * The waking up of stopper threads has to happen + * in the same scheduling context as the queueing. + * Otherwise, there is a possibility of one of the + * above stoppers being woken up by another CPU, + * and preempting us. This will cause us to n ot + * wake up the other stopper forever. + */ + preempt_disable(); unlock: raw_spin_unlock(&stopper2->lock); raw_spin_unlock_irq(&stopper1->lock); @@ -271,7 +280,6 @@ unlock: } if (!err) { - preempt_disable(); wake_up_q(&wakeq); preempt_enable(); } |