sched/core: Avoid double update_rq_clock() in move_queued_task()

Address this case:

  WARNING: CPU: 0 PID: 2070 at ../kernel/sched/core.c:109 update_rq_clock+0x74/0x80
  rq->clock_update_flags & RQCF_UPDATED

  Call Trace:
  update_rq_clock()
  move_queued_task()
  __set_cpus_allowed_ptr()
  ...

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c6be770..c762f62 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -948,7 +948,7 @@ static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
        lockdep_assert_held(&rq->lock);
 
        p->on_rq = TASK_ON_RQ_MIGRATING;
-       dequeue_task(rq, p, 0);
+       dequeue_task(rq, p, DEQUEUE_NOCLOCK);
        set_task_cpu(p, new_cpu);
        rq_unlock(rq, rf);
 
@@ -987,6 +987,7 @@ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
        if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
                return rq;
 
+       update_rq_clock(rq);
        rq = move_queued_task(rq, rf, p, dest_cpu);
 
        return rq;