From: Greg KH <gregkh@linuxfoundation.org>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
Jiri Slaby <jirislaby@gmail.com>
Subject: Re: [PATCH 3/3] tty_lock: Localise the lock
Date: Fri, 11 May 2012 07:52:43 -0700 [thread overview]
Message-ID: <20120511145243.GE5958@kroah.com> (raw)
In-Reply-To: <CA+1xoqcZnxGoo=_X1idCPTk9gR=drnAKhULGzgkH33zYGnAgOA@mail.gmail.com>
On Fri, May 11, 2012 at 12:40:41PM +0200, Sasha Levin wrote:
> On Tue, May 8, 2012 at 8:12 PM, Sasha Levin <levinsasha928@gmail.com> wrote:
> > On Mon, May 7, 2012 at 11:04 PM, Jiri Slaby <jslaby@suse.cz> 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.
>
> I've applied the patch that unlocks before hangup, and started seeing
> this new warning instead (sorry if output below looks a bit broken,
> linux-next has a printk rework in progress):
The printk rework should now be working again in linux-next. Is it
still causing problems for you?
thanks,
greg k-h
next prev parent reply other threads:[~2012-05-11 14:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-03 21:21 [PATCH 1/3] tty_lock: undo the old tty_lock use on the ctty Alan Cox
2012-05-03 21:22 ` [PATCH 2/3] pty: Lock the devpts bits privately Alan Cox
2012-05-08 18:18 ` H. Peter Anvin
2012-05-08 20:43 ` Alan Cox
2012-05-08 20:41 ` H. Peter Anvin
2012-05-03 21:24 ` [PATCH 3/3] tty_lock: Localise the lock Alan Cox
2012-05-04 20:48 ` Arnd Bergmann
2012-05-04 23:54 ` Greg KH
2012-05-04 23:55 ` Greg KH
2012-05-07 16:03 ` Sasha Levin
2012-05-07 16:11 ` Alan Cox
2012-05-07 16:30 ` Sasha Levin
2012-05-07 16:42 ` Alan Cox
2012-05-07 17:00 ` Sasha Levin
2012-05-07 21:04 ` Jiri Slaby
2012-05-08 18:12 ` Sasha Levin
2012-05-11 10:40 ` Sasha Levin
2012-05-11 14:52 ` Greg KH [this message]
2012-05-11 15:09 ` Sasha Levin
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