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Message-ID: <19f34abd0807231339i4ba524d6u27f1c4054197a81@mail.gmail.com>
Date: Wed, 23 Jul 2008 22:39:22 +0200
From: "Vegard Nossum" <vegard.nossum@gmail.com>
To: "Suresh Siddha" <suresh.b.siddha@intel.com>
Subject: Re: recent -git: BUG in free_thread_xstate
Cc: LKML <linux-kernel@vger.kernel.org>,
       "the arch/x86 maintainers" <x86@kernel.org>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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Hi!

On Wed, Jul 23, 2008 at 10:31 PM, Suresh Siddha
<suresh.b.siddha@intel.com> wrote:
> On Wed, Jul 23, 2008 at 01:07:04PM -0700, Vegard Nossum wrote:
>> Hi,
>>
>> I just got this on c010b2f76c3032e48097a6eef291d8593d5d79a6 (-git from
>> yesterday):
>
> Do you see this in 2.6.26 aswell? I suspect it is coming from post 2.6.26
> changes.

Just reproduced it on latest linux-2.6.git.

>> BUG: unable to handle kernel paging request at 00664381
>> IP: [<c010b274>] free_thread_xstate+0x4/0x30
> ...
>

The funny thing is that this number (00664281) is _always_ the same,
even on the newer kernel. What's special about it?

>> EIP is at arch/x86/kernel/process.c:36:
>>
>>         if (tsk->thread.xstate) {
>>
>
> It looks like the kernel stack of that process got corrupted, corrupting the
> task pointer in thread_info. Can you send us your config file?

It has been uploaded here:

http://userweb.kernel.org/~vegard/bugs/20080724-fork/config

Given the reproducible nature of this, I think I'll just go ahead and
start a bisect...

Thanks for looking :-)


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036