sched/core: Add missing update_rq_clock() call in set_user_nice()

Peter Zijlstra · Ingo Molnar · commit 2fb8d36787af · 2017-01-14T11:29:34.000+01:00
Address this rq-clock update bug:

  WARNING: CPU: 30 PID: 195 at ../kernel/sched/sched.h:797 set_next_entity()
  rq-&gt;clock_update_flags &lt; RQCF_ACT_SKIP

  Call Trace:
    dump_stack()
    __warn()
    warn_slowpath_fmt()
    set_next_entity()
    ? _raw_spin_lock()
    set_curr_task_fair()
    set_user_nice.part.85()
    set_user_nice()
    create_worker()
    worker_thread()
    kthread()
    ret_from_fork()

Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Mike Galbraith &lt;efault@gmx.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -3752,6 +3752,8 @@ void set_user_nice(struct task_struct *p, long nice)
 	 * the task might be in the middle of scheduling on another CPU.
 	 */
 	rq = task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+
 	/*
 	 * The RT priorities are set via sched_setscheduler(), but we still
 	 * allow the 'normal' nice value to be set - but as expected
