Messages in this thread | | | Date | Mon, 28 Oct 2013 15:50:10 +0100 | From | Knut Petersen <> | Subject | Re: [BUG 3.12.rc4] Oops: unable to handle kernel paging request during shutdown |
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On 26.10.2013 13:43, Ingo Molnar wrote: > * Linus Torvalds <torvalds@linux-foundation.org> wrote: > >> On Fri, Oct 25, 2013 at 11:23 AM, Thomas Gleixner <tglx@linutronix.de> wrote: >>> Enable DEBUG_OBJECTS, DEBUG_OBJECTS_FREE, DEBUG_OBJECTS_TIMERS >> Yes, but nobody has actually been able to trigger it with those. >> It's pretty rare, and the debug options are so expensive that they >> aren't reasonable to enable generally... >> >> So we need to try to figure out how to trigger it, or narrow >> things down some way.. > If it's timing then maybe the 1 seconds delay isn't enough > (especially if it's boot related, where we have a couple of delays > already) - the patch below triples it. > > (If the bug goes away due to some other side effect then this patch > won't make a difference to reproducability.)
I tried that patch, together with all the kobj debug options enabled. With that kernel configuration I was unable to reproduce the problem during 500 typical workload / reboot cycles. Without the debug options I was able to reproduce the last reported panic after 91 cycles. The debug options seem to change timing sufficiently to mask the bug ;-(
Knut
> Thanks, > > Ingo > > diff --git a/lib/kobject.c b/lib/kobject.c > index 084f7b1..124188f 100644 > --- a/lib/kobject.c > +++ b/lib/kobject.c > @@ -595,7 +595,7 @@ static void kobject_release(struct kref *kref) > pr_info("kobject: '%s' (%p): %s, parent %p (delayed)\n", > kobject_name(kobj), kobj, __func__, kobj->parent); > INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup); > - schedule_delayed_work(&kobj->release, HZ); > + schedule_delayed_work(&kobj->release, 3*HZ); > #else > kobject_cleanup(kobj); > #endif >
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