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SubjectRe: Linux 3.6-rc4
Al? Please look into this. I'm not entirely sure what's going on, but
lockdep complains about this:

Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&(&p->alloc_lock)->rlock);
local_irq_disable();
lock(&(&new_timer->it_lock)->rlock);
lock(tasklist_lock);
<Interrupt>
lock(&(&new_timer->it_lock)->rlock);

*** DEADLOCK ***

and it looks real. IOW, if I read that right, we have the task_lock ->
it_lock dependency through exit_itimers(), and then we have the
tasklist_lock -> task_lock dependency everywhere else. So now it_lock
-> tasklist_lock becomes a deadlock.

Linus

On Fri, Sep 7, 2012 at 10:55 AM, Sasha Levin <levinsasha928@gmail.com> wrote:
> On 09/04/2012 05:44 PM, Dave Jones wrote:
>> On Sat, Sep 01, 2012 at 03:10:58PM -0700, Linus Torvalds wrote:
>> > The kernel summit is over, and most people have either returned or are
>> > returning from San Diego.
>>
>> Still seeing this, that I started seeing just before leaving for San Diego..
>>
>> Dave
>
> I've bisected this one down to
>
>
> d35abdb28824cf74f0a106a0f9c6f3ff700a35bf is the first bad commit
> commit d35abdb28824cf74f0a106a0f9c6f3ff700a35bf
> Author: Al Viro <viro@zeniv.linux.org.uk>
> Date: Sat Jun 30 11:55:24 2012 +0400
>
> hold task_lock around checks in keyctl
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
>
>
> Just didn't get a response from anyone when I've mailed about it...


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