From: Knut Petersen <Knut_Petersen@t-online.de>
To: Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
"Paul McKenney" <paulmck@linux.vnet.ibm.com>,
"Frédéric Weisbecker" <fweisbec@gmail.com>,
"Greg KH" <greg@kroah.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BUG 3.12.rc4] Oops: unable to handle kernel paging request during shutdown
Date: Mon, 28 Oct 2013 15:50:10 +0100 [thread overview]
Message-ID: <526E79A2.9080303@t-online.de> (raw)
In-Reply-To: <20131026114303.GA24067@gmail.com>
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
>
next prev parent reply other threads:[~2013-10-28 14:50 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <525BD08C.2080101@t-online.de>
2013-10-14 17:53 ` [BUG 3.12.rc4] Oops: unable to handle kernel paging request during shutdown Linus Torvalds
2013-10-14 21:28 ` Paul E. McKenney
2013-10-14 21:51 ` Frederic Weisbecker
2013-10-14 22:31 ` Knut Petersen
2013-10-14 22:43 ` Frederic Weisbecker
2013-10-15 6:40 ` Ingo Molnar
2013-10-15 7:53 ` Knut Petersen
2013-10-17 14:25 ` Frederic Weisbecker
2013-10-18 6:30 ` Ingo Molnar
2013-10-14 21:52 ` Knut Petersen
2013-10-14 23:16 ` Paul E. McKenney
2013-10-15 0:59 ` Paul E. McKenney
2013-10-15 8:06 ` Knut Petersen
2013-10-25 8:38 ` Linus Torvalds
2013-10-25 9:02 ` Linus Torvalds
2013-10-25 9:08 ` Paul E. McKenney
2013-10-25 9:17 ` Greg Kroah-Hartman
2013-10-25 9:13 ` Greg Kroah-Hartman
2013-10-25 9:28 ` Rafael J. Wysocki
2013-10-25 9:51 ` Rafael J. Wysocki
2013-10-25 9:54 ` Viresh Kumar
2013-10-25 10:10 ` Rafael J. Wysocki
2013-10-25 10:00 ` Viresh Kumar
2013-10-25 10:07 ` Linus Torvalds
2013-10-25 11:10 ` Rafael J. Wysocki
2013-10-25 13:49 ` Viresh Kumar
2013-10-25 14:21 ` Rafael J. Wysocki
2013-10-28 15:02 ` Knut Petersen
2013-10-25 10:23 ` Thomas Gleixner
2013-10-25 10:48 ` Linus Torvalds
2013-10-26 11:43 ` Ingo Molnar
2013-10-28 14:50 ` Knut Petersen [this message]
2013-10-28 15:01 ` Ingo Molnar
2013-10-28 15:16 ` Ingo Molnar
2013-10-28 15:45 ` Knut Petersen
2013-10-27 20:20 ` Linus Torvalds
2013-10-27 20:39 ` Linus Torvalds
2013-10-27 21:13 ` Linus Torvalds
2013-10-27 21:24 ` Greg Kroah-Hartman
2013-10-28 17:23 ` Bjorn Helgaas
2013-10-28 17:30 ` Veaceslav Falico
2013-10-28 17:35 ` Bjorn Helgaas
2013-10-28 17:39 ` Veaceslav Falico
2013-10-28 18:52 ` Greg Kroah-Hartman
2013-10-30 18:04 ` Pablo Neira Ayuso
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