On Fri, Aug 1, 2014 at 12:56 PM, Al Viro <[email protected]> wrote: > > On Fri, Aug 01, 2014 at 12:06:12PM -0400, Jeff Harris wrote: > > > + spin_lock(&c->wbuf_dwork_lock); > > cancel_delayed_work_sync(&c->wbuf_dwork); > > Umm... Usually ..._sync in function name is a sign of potential sleeper, > and calling those under a spinlock is a bad idea. > > And looking at the definition of cancel_delayed_work_sync() turns up the > following call chain: cancel_delayed_work_sync() -> __cancel_work_timer() -> > flush_work() -> wait_for_completion(), which definitely isn't something > you should ever do under a spinlock.
The jffs2_dirty_trigger function calls queue_delayed_work under the spinlock. I suppose the flag could be reset after the cancel so the dirty trigger would see the false value. > > > While we are at it, you follow that with > > + c->wbuf_queued = 0; > > + spin_lock(&c->wbuf_dwork_lock); > which would be broken even if cancel_delayed_work_sync() hadn't blocked. > That's easily fixed, of course, (s/lock/unlock/). cancel_delayed_work_sync() > under a spinlock is more serious... Whoops, sorry about that. Jeff -- 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/
