4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Juri Lelli <[email protected]>

commit 4cd57f97135840f637431c92380c8da3edbe44ed upstream.

dl_task_timer() may fire on a different rq from where a task was removed
after throttling. Since the call path is:

  dl_task_timer() ->
    enqueue_task_dl() ->
      enqueue_dl_entity() ->
        replenish_dl_entity()

and replenish_dl_entity() uses dl_se's rq, we can't use current's rq
in dl_task_timer(), but we need to lock the task's previous one.

Tested-by: Wanpeng Li <[email protected]>
Signed-off-by: Juri Lelli <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Kirill Tkhai <[email protected]>
Cc: Juri Lelli <[email protected]>
Fixes: 3960c8c0c789 ("sched: Make dl_task_time() use task_rq_lock()")
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 kernel/sched/deadline.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -514,7 +514,7 @@ static enum hrtimer_restart dl_task_time
        unsigned long flags;
        struct rq *rq;
 
-       rq = task_rq_lock(current, &flags);
+       rq = task_rq_lock(p, &flags);
 
        /*
         * We need to take care of several possible races here:
@@ -569,7 +569,7 @@ static enum hrtimer_restart dl_task_time
                push_dl_task(rq);
 #endif
 unlock:
-       task_rq_unlock(rq, current, &flags);
+       task_rq_unlock(rq, p, &flags);
 
        return HRTIMER_NORESTART;
 }


--
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/

Reply via email to