Messages in this thread | | | Date | Thu, 2 Oct 2014 21:11:14 +0200 | From | Oleg Nesterov <> | Subject | Re: [rfcomm_run] WARNING: CPU: 1 PID: 79 at kernel/sched/core.c:7156 __might_sleep() |
| |
On 10/02, Peter Zijlstra wrote: > > On Thu, Oct 02, 2014 at 03:52:50PM +0200, Peter Zijlstra wrote: > > > If yes, then wakeups from signals don't work either, right? > > > > Its a kthread, there should not be any signals. > > That said, in the tty patch we do appear to have this problem. > > Oleg, do we want something like the below on top to make that work > again? > > --- > --- a/kernel/sched/wait.c > +++ b/kernel/sched/wait.c > @@ -326,8 +326,10 @@ long wait_woken(wait_queue_t *wait, unsi > * woken_wake_function() such that if we observe WQ_FLAG_WOKEN we must > * also observe all state before the wakeup. > */ > - if (!(wait->flags & WQ_FLAG_WOKEN)) > - timeout = schedule_timeout(timeout); > + if (!(wait->flags & WQ_FLAG_WOKEN)) { > + if (___wait_is_interruptible(mode) && !signal_pending_state(mode, current)) > + timeout = schedule_timeout(timeout); > + } > __set_current_state(TASK_RUNNING);
I am a bit confused... but for what?
schedule() won't sleep if signal_pending_state(mode) anyway, so we do not need this correctness-wise. And the caller needs to check signal_pending() anyway.
We can probably add
if (signal_pending_state(mode, current)) return -EINTR;
at the start of wait_woken(), even before set_current_state(mode). Then the caller can check "ret < 0" and avoid signal_pending(). Not sure this makes sense.
Oleg.
| |