Messages in this thread | | | Date | Thu, 2 Oct 2014 15:52:50 +0200 | From | Peter Zijlstra <> | Subject | Re: [rfcomm_run] WARNING: CPU: 1 PID: 79 at kernel/sched/core.c:7156 __might_sleep() |
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On Thu, Oct 02, 2014 at 09:49:04AM -0400, Peter Hurley wrote: > On 10/02/2014 08:42 AM, Peter Zijlstra wrote: > > On Thu, Oct 02, 2014 at 02:31:50PM +0200, Peter Zijlstra wrote: > >> @@ -2086,24 +2086,22 @@ static void rfcomm_kill_listener(void) > >> > >> static int rfcomm_run(void *unused) > >> { > >> + DEFINE_WAIT_FUNC(wait, woken_wake_function); > >> BT_DBG(""); > >> > >> set_user_nice(current, -10); > >> > >> rfcomm_add_listener(BDADDR_ANY); > >> > >> - while (1) { > >> - set_current_state(TASK_INTERRUPTIBLE); > >> - > >> - if (kthread_should_stop()) > >> - break; > >> + add_wait_queue(&rfcomm_wq, &wait); > >> + while (!kthread_should_stop()) { > >> > >> /* Process stuff */ > >> rfcomm_process_sessions(); > >> > >> - schedule(); > >> + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); > >> } > >> - __set_current_state(TASK_RUNNING); > >> + remove_wait_queue(&rfcomm_wq, &wait); > >> > >> rfcomm_kill_listener(); > >> > > > > Hmm, I think there's a problem there. If someone were to do > > kthread_stop() before wait_woken() we'd not actually stop, because > > wait_woken() doesn't test KTHREAD_SHOULD_STOP before calling schedule(). > > Do you mean this situation? > > CPU 0 | CPU 1 > | > rfcomm_run() | kthread_stop() > ... | > if (!test_bit(KTHREAD_SHOULD_STOP)) | > | set_bit(KTHREAD_SHOULD_STOP) > | wake_up_process() > wait_woken() | wait_for_completion() > set_current_state(INTERRUPTIBLE) | > if (!WQ_FLAG_WOKEN) | > schedule_timeout() | > | > > Now both tasks are sleeping forever.
Yep.
> If yes, then wakeups from signals don't work either, right?
Its a kthread, there should not be any signals.
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