linux-kernel - Re: crash in 3.12.51 (likely in 3.12.52 as well) in timer code

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Date:	Thu, 4 Feb 2016 09:56:00 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Nikolay Borisov <kernel@...p.com>
cc:	"Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>,
	Jiri Slaby <jslaby@...e.cz>, Oleg Nesterov <oleg@...hat.com>,
	SiteGround Operations <operations@...eground.com>
Subject: Re: crash in 3.12.51 (likely in 3.12.52 as well) in timer code

On Wed, 3 Feb 2016, Nikolay Borisov wrote:
> 
> It seems when the code tries to do prev->next = next in __list_del from detach_timer, 
> rax has a value of dead000000200200 (LIST_POISON2).

> So in this case the prev/next entries do not look like corrupted, whereas
> when manipulating the list inside detach_timer they do. This is really
> odd, any ideas how to further debug this?

Please enable

CONFIG_DEBUG_OBJECTS
CONFIG_DEBUG_OBJECTS_TIMERS
CONFIG_DEBUG_OBJECTS_WORK

That should pinpoint the offending code.

Thanks,

	tglx