Re: [2.6.33-rc5] starting emacs makes lockdep warning

From: AmÃrico Wang
Date: Tue Jan 26 2010 - 01:01:19 EST


On Tue, Jan 26, 2010 at 1:49 PM, KOSAKI Motohiro
<kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>> > On Tue, Jan 26, 2010 at 11:20 AM, KOSAKI Motohiro
>> > <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>> > > Hi
>> > >
>> > > Current linus tree made following lockdep warning when starting emacs command.
>> > > Is this known issue?
>> > >
>> > >
>> > > =========================================================
>> > > [ INFO: possible irq lock inversion dependency detected ]
>> > > 2.6.33-rc5 #77
>> > > ---------------------------------------------------------
>> > > emacs/1609 just changed the state of lock:
>> > > Â(&(&tty->ctrl_lock)->rlock){+.....}, at: [<ffffffff8127c648>] tty_fasync+0xe8/0x190
>> > > but this lock took another, HARDIRQ-unsafe lock in the past:
>> > > Â(&(&sighand->siglock)->rlock){-.....}
>> > >
>> > > and interrupts could create inverse lock ordering between them.
>> > >
>> > >
>> >
>> > Hey,
>> >
>> > does reverting commit 703625118 help?
>>
>> Seems solved.
>>
>> Thanks.
>
> I'm sorry.
> I forgot to cc related person at last mail.
>
> Greg, can you please consider revert commit 703625118?
>

I agree, it seems that patch is useless, since we already
do lock_kernel() before calling __f_setown()...
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/