Re: tasklist_lock lockdep warnings on 3.6

From: Sasha Levin
Date: Tue Aug 07 2012 - 10:26:48 EST


On 08/02/2012 04:16 PM, Sasha Levin wrote:
> On 08/02/2012 03:26 PM, Dave Jones wrote:
>> On Mon, Jul 30, 2012 at 04:50:46PM +0200, Sasha Levin wrote:
>> > ping?
>> >
>> > I'm still seeing this on linux-next.
>>
>> Likewise, except I'm seeing it in Linus' tree since shortly after this merge window
>> began. (https://lkml.org/lkml/2012/7/24/443).
>>
>> I've spent all of this last week doing multiple attempts at bisecting this without success.
>> (It doesn't always show up, and even after running the test for over an hour before
>> marking a build 'good')
>>
>> Anyone ?
>>
>> Dave
>
> I've been able to hit this issue pretty much every time by hitting sysrq-t after about 10 seconds of fuzzing. It shows up in the middle of the sysrq-t spew.
>
> Unfortunately I didn't have time yet to try and bisect it.
>

So I've bisected it. The bisection was automatic most of the time, but I've confirmed that this is indeed the offending commit manually.

d35abdb28824cf74f0a106a0f9c6f3ff700a35bf is the first bad commit
commit d35abdb28824cf74f0a106a0f9c6f3ff700a35bf
Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Sat Jun 30 11:55:24 2012 +0400

hold task_lock around checks in keyctl

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>


Relevant parties Cc'ed.
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