Eric Wong <normalperson@xxxxxxxx> wrote: > Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > > commit 626cf236608505d376e4799adb4f7eb00a8594af should not have this > > side effect, at least for poll()/select() functions. The epoll() changes > > I am not yet very confident. > > I have a better explanation of the epoll problem below. > > An alternate version (limited to epoll) would be: > > diff --git a/fs/eventpoll.c b/fs/eventpoll.c > index cd96649..ca5f3d0 100644 > --- a/fs/eventpoll.c > +++ b/fs/eventpoll.c > @@ -1299,6 +1299,7 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even > * Get current event bits. We can safely use the file* here because > * its usage count has been increased by the caller of this function. > */ > + smp_mb(); > revents = epi->ffd.file->f_op->poll(epi->ffd.file, &pt); > > /* > > > I suspect a race already existed before this commit, it would be nice to > > track it properly. > > I don't believe this race existed before that change. I was wrong, rereading 626cf236608505d376e4799adb4f7eb00a8594af, I think this race existed before. Perhaps my alternate patch above is a better fix. -- 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
