On Mon, Sep 5, 2016 at 3:08 PM, Tejun Heo <t...@kernel.org> wrote: > Hello, > > On Sat, Sep 03, 2016 at 12:58:33PM +0200, Dmitry Vyukov wrote: >> > I've seen it only several times in several months, so I don't it will >> > be helpful. >> >> >> Bad news: I hit it again. >> On 0f98f121e1670eaa2a2fbb675e07d6ba7f0e146f of linux-next, so I have >> bf389cabb3b8079c23f9762e62b05f291e2d5e99. > > Hmmm... we're not getting anywhere. I've applied the following patch > to wq/for-4.8-fixes so that when this happens the next time we can > actually tell what the hell is going wrong. > > Thanks. > > ------ 8< ------ > From 278930ada88c972d20025b0f20def27b1a09dff7 Mon Sep 17 00:00:00 2001 > From: Tejun Heo <t...@kernel.org> > Date: Mon, 5 Sep 2016 08:54:06 -0400 > Subject: [PATCH] workqueue: dump workqueue state on sanity check failures in > destroy_workqueue() > > destroy_workqueue() performs a number of sanity checks to ensure that > the workqueue is empty before proceeding with destruction. However, > it's not always easy to tell what's going on just from the warning > message. Let's dump workqueue state after sanity check failures to > help debugging. > > Signed-off-by: Tejun Heo <t...@kernel.org> > Link: > http://lkml.kernel.org/r/cact4y+zs6vkjho9qhb4treiz3s4+quvvvq9vwvj2mx6petg...@mail.gmail.com > Cc: Dmitry Vyukov <dvyu...@google.com> > --- > kernel/workqueue.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index ef071ca..4eaec8b8 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -4021,6 +4021,7 @@ void destroy_workqueue(struct workqueue_struct *wq) > for (i = 0; i < WORK_NR_COLORS; i++) { > if (WARN_ON(pwq->nr_in_flight[i])) { > mutex_unlock(&wq->mutex); > + show_workqueue_state(); > return; > } > } > @@ -4029,6 +4030,7 @@ void destroy_workqueue(struct workqueue_struct *wq) > WARN_ON(pwq->nr_active) || > WARN_ON(!list_empty(&pwq->delayed_works))) { > mutex_unlock(&wq->mutex); > + show_workqueue_state(); > return; > } > }
Applied this to my test tree.
