On 12/6/18 11:15 AM, Sebastian Andrzej Siewior wrote: > There is a small window between setting t->task to NULL and waking the > task up (which would set TASK_RUNNING). So the timer would fire, run and > set ->task to NULL while the other side/do_nanosleep() wouldn't enter > freezable_schedule(). After all we are peemptible here (in > do_nanosleep() and on the timer wake up path) and on KVM/virt the > virt-CPU might get preempted. > So do_nanosleep() wouldn't enter freezable_schedule() but cancel the > timer which is still running and wait for it via > hrtimer_wait_for_timer(). Then wait_event()/might_sleep() would complain > that it is invoked with state != TASK_RUNNING. > This isn't a problem since it would be reset to TASK_RUNNING later > anyway and we don't rely on the previous state. > > Move the state update to TASK_RUNNING before hrtimer_cancel() so there > are no complains from might_sleep() about wrong state. > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Reviewed-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Thanks! -- Daniel
