linux-kernel - Re: [PATCH 1/1] timer: Warn about schedule_timeout() called for tasks in TASK

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Message-ID: <20200116095507.6f164a0a@gandalf.local.home>
Date:   Thu, 16 Jan 2020 09:55:07 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Alexander Popov <alex.popov@...ux.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        John Stultz <john.stultz@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Stephen Boyd <sboyd@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        linux-kernel@...r.kernel.org, notify@...nel.org
Subject: Re: [PATCH 1/1] timer: Warn about schedule_timeout() called for
 tasks in TASK_RUNNING state

On Thu, 16 Jan 2020 09:52:20 -0500
Steven Rostedt <rostedt@...dmis.org> wrote:

> > --- a/kernel/time/timer.c
> > +++ b/kernel/time/timer.c
> > @@ -1887,6 +1887,11 @@ signed long __sched schedule_timeout(signed long timeout)
> >  		}
> >  	}
> >  
> > +#ifdef CONFIG_SCHED_DEBUG
> > +	WARN_ONCE(current->state == TASK_RUNNING,
> > +			"schedule_timeout for TASK_RUNNING\n");
> > +#endif
> > +  
> 
> But this can trigger false warnings. For example, if we are waiting on
> an event with a timeout:


Also, there are helpers here that you can use:

schedule_timeout_interruptible(signed long timeout);
schedule_timeout_uninterruptible(signed long timeout)

-- Steve