On Sun, 16 Aug 2009 09:53:08 +0900 Tejun Heo <tj@xxxxxxxxxx> wrote: > Guillaume Knispel wrote: > > poll/select: initialize triggered field of struct poll_wqueues > > > > The triggered field of struct poll_wqueues introduced in commit > > 5f820f648c92a5ecc771a96b3c29aa6e90013bba "poll: allow f_op->poll to > > sleep" was set to 1 in pollwake() (now __pollwake() ), tested and > > later set to 0 in poll_schedule_timeout(), but not initialized before. > > As a result when the process needs to sleep, triggered was likely to be > > non-zero even if pollwake() is not called before the first > > poll_schedule_timeout(), meaning schedule_hrtimeout_range() would not > > be called and an extra loop calling all ->poll() would be done. > > > > This patch initialize triggered to 0 in poll_initwait() so the ->poll() > > are not called twice before the process goes to sleep when it needs to. > > > > Signed-off-by: Guillaume Knispel <gknispel@xxxxxxxxxxxxxxxxx> > > Ah... nice spotting. > > Acked-by: Tejun Heo <tj@xxxxxxxxxx> > OK, thanks. I tagged this for -stable backporting. That isn't strictly needed, as there's no particular harm caused here. But using an uninitialised variable in the core poll/select code is pretty gross. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
