From: Linus Torvalds <torvalds@linux-foundation.org>
To: Sasha Levin <levinsasha928@gmail.com>, Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Jones <davej@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: Linux 3.6-rc4
Date: Fri, 7 Sep 2012 11:39:43 -0700 [thread overview]
Message-ID: <CA+55aFwh5kUDC_5-_4_TkqnQU73sotAkOs166ag4R3Fx8VKffw@mail.gmail.com> (raw)
In-Reply-To: <504A3527.9070104@gmail.com>
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...
next prev parent reply other threads:[~2012-09-07 18:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-01 22:10 Linux 3.6-rc4 Linus Torvalds
2012-09-04 15:44 ` Dave Jones
2012-09-07 17:55 ` Sasha Levin
2012-09-07 18:39 ` Linus Torvalds [this message]
2012-09-10 14:36 ` Peter Zijlstra
2012-09-15 12:25 ` Sasha Levin
2012-09-21 21:16 ` Dave Jones
2012-09-28 19:05 ` Dave Jones
2012-10-01 20:55 ` Linus Torvalds
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