On Thu, May 2, 2013 at 10:58 AM, Imre Deak <[email protected]> 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 <[email protected]>
We have 3 instances of this bug in drm/i915. One case even where we switch between the interruptible and not interruptible wait_event_timeout variants, foolishly presuming they have the same semantics. I very much like this. Acked-by: Daniel Vetter <[email protected]> -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
