Re: [PATCH] wait: fix false timeouts when using wait_event_timeout()

From: Jens Axboe
Date: Thu May 02 2013 - 08:35:42 EST


On Thu, May 02 2013, David Howells wrote:
> Imre Deak <imre.deak@xxxxxxxxx> wrote:
>
> > Many callers of the wait_event_timeout() and
> > wait_event_interruptible_timeout() expect that the return value will be
> > positive if the specified condition becomes true before the timeout
> > elapses. However, at the moment this isn't guaranteed. If the wake-up
> > handler is delayed enough, the time remaining until timeout will be
> > calculated as 0 - and passed back as a return value - even if the
> > condition became true before the timeout has passed.
> >
> > Fix this by returning at least 1 if the condition becomes true. This
> > semantic is in line with what wait_for_condition_timeout() does; see
> > commit bb10ed09 - "sched: fix wait_for_completion_timeout() spurious
> > failure under heavy load".
> >
> > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
>
> Acked-by: David Howells <dhowells@xxxxxxxxxx>

You can add mine, too:

Acked-by: Jens Axboe <axboe@xxxxxxxxx>

--
Jens Axboe

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