Messages in this thread | | | Date | Fri, 3 Oct 2014 19:56:54 +0200 | From | Oleg Nesterov <> | Subject | Re: [rfcomm_run] WARNING: CPU: 1 PID: 79 at kernel/sched/core.c:7156 __might_sleep() |
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On 10/03, Peter Zijlstra wrote: > > On Thu, Oct 02, 2014 at 10:10:20PM +0200, Oleg Nesterov wrote: > > > As for rfcomm_run(), perhaps it can ise it too? > > > > set_kthread_wants_signal(true); > > > > add_wait_queue(&rfcomm_wq, &wait); > > for (;;) { > > // This is only possible if kthread_should_stop() == T > > True because kthreads SIG_IGN everything, right?
Yes,
> > if (signal_pending(current)) > > break; > > > > rfcomm_process_sessions(); > > wait_woken(TASK_INTERRUPTIBLE); > > } > > > > Of course, this assumes that rfcomm_process_sessions() can't do something > > "really bad" if signal_pending() is true. > > So from what I can think of, everything that does an INTERRUPTIBLE sleep > will 'malfunction' after that, right? Which might be quite a lot > actually.
Yes.
> > What do you think? > > Interesting approach, but somewhat risky I tihnk, due to that > INTERRUPTIBLE thing.
OK, this is fixable. rfcomm_run() can do
add_wait_queue(&rfcomm_wq, &wait); while (!kthread_should_stop()) { rfcomm_process_sessions();
set_kthread_wants_signal(true); wait_woken(TASK_INTERRUPTIBLE); set_kthread_wants_signal(false); } remove_wait_queue(&rfcomm_wq, &wait);
Or. perhaps we can change wait_woken
- set_current_state(mode); + if (mode) + set_current_state(mode);
then rfcomm_run() can do
for (;;) { rfcomm_process_sessions();
set_current_state(TASK_INTERRUPTIBLE); if (kthread_should_stop()) break; wait_woken(0); }
Or perhaps we can split wait_woken() into 2 helpers,
static inline long wait_woken(wq, mode, timeout) { set_current_state(mode); schedule_woken(wq, timeout); // does the rest }
to avoid "mode == 0" hack; rfcomm_run() should use schedule_woken().
What do you think?
Oleg.
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