diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-10-08 21:36:44 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-10-28 10:47:54 +0100 |
| commit | 1a43a14a5bd9c32dbd7af35e35a5afa703944bcb (patch) | |
| tree | dbbef5740b8e0851eef0c19760e548529076613c /kernel/sched | |
| parent | sched: Fix the PREEMPT_ACTIVE check in __trace_sched_switch_state() (diff) | |
| download | linux-1a43a14a5bd9c32dbd7af35e35a5afa703944bcb.tar.xz linux-1a43a14a5bd9c32dbd7af35e35a5afa703944bcb.zip | |
sched: Fix schedule_tail() to disable preemption
finish_task_switch() enables preemption, so post_schedule(rq) can be
called on the wrong (and even dead) CPU. Afaics, nothing really bad
can happen, but in this case we can wrongly clear rq->post_schedule
on that CPU. And this simply looks wrong in any case.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20141008193644.GA32055@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cde848149dd6..b4935600cd85 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2309,15 +2309,14 @@ static inline void post_schedule(struct rq *rq) asmlinkage __visible void schedule_tail(struct task_struct *prev) __releases(rq->lock) { - struct rq *rq = this_rq(); + struct rq *rq; + /* finish_task_switch() drops rq->lock and enables preemtion */ + preempt_disable(); + rq = this_rq(); finish_task_switch(rq, prev); - - /* - * FIXME: do we need to worry about rq being invalidated by the - * task_switch? - */ post_schedule(rq); + preempt_enable(); if (current->set_child_tid) put_user(task_pid_vnr(current), current->set_child_tid); |