Re: [PATCH 3/3] tty_lock: Localise the lock

[Sasha Levin]

On Mon, May 7, 2012 at 11:04 PM, Jiri Slaby <jslaby@xxxxxxx> wrote:
> On 05/07/2012 07:00 PM, Sasha Levin wrote:
>>> So whatever your trace is showing, that's not the bug. Something more
>>> complicated would appear to be afoot.
>>
>> Oddly enough, tty != tty->link, but the lockdep warning triggers.
>>
>> Any idea why it might happen?
>
> I think so, both locks are the same lockdep class. So lockdep thinks it
> is the same lock. However this is a false positive. I guess we need
> mutex_lock_nested...

It looks like it causes an actual deadlock, and hung_tasks screams if
left alone for a bit, so it doesn't look like a lockdep issue.
--
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/