Commit-ID: 1a43a14a5bd9c32dbd7af35e35a5afa703944bcb Gitweb: http://git.kernel.org/tip/1a43a14a5bd9c32dbd7af35e35a5afa703944bcb Author: Oleg Nesterov <[email protected]> AuthorDate: Wed, 8 Oct 2014 21:36:44 +0200 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 28 Oct 2014 10:47:54 +0100
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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Kirill Tkhai <[email protected]> Cc: Linus Torvalds <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- kernel/sched/core.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cde8481..b493560 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
