From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Josh Boyer <jwboyer@gmail.com>
Cc: linux-kernel@vger.kernel.org, florianschandinat@gmx.de
Subject: Re: [PATCH] fb: Rework locking to fix lock ordering on takeover
Date: Wed, 21 Nov 2012 12:53:10 +0000 [thread overview]
Message-ID: <20121121125310.00625f55@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <CA+5PVA6nKNZY70UoeDUhQo9Rj4Ck+k+XTHL++gwErgzqAdy6Aw@mail.gmail.com>
On Wed, 21 Nov 2012 07:45:45 -0500
Josh Boyer <jwboyer@gmail.com> wrote:
> On Fri, Nov 16, 2012 at 2:27 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> >
> > [The fb maintainer appears to be absent at the moment].
> >
> > This is needed to fix a pile of lockdep splats that now show up because console_lock()
> > is being properly audited. Hugh Dickins and Sasha Levin have tested it and both reports
> > all looks good. This is probably not the whole story - the entire fb layer has locking
> > confusion problems that were previously hidden but it seems to get the ones people hit
> > in testing. This hopefully explains a few of the weird fb hangs that have been floating
> > around forever.
> >
> > From: Alan Cox <alan@linux.intel.com>
> >
> > Adjust the console layer to allow a take over call where the caller already
> > holds the locks. Make the fb layer lock in order.
> >
> > This s partly a band aid, the fb layer is terminally confused about the
> > locking rules it uses for its notifiers it seems.
> >
> > Signed-off-by: Alan Cox <alan@linux.intel.com>
>
> Should this eventually get into the stable trees?
Thats a question I'm not sure about at this point. I think the bug is
real but not caught by the lock checker in older trees but I've not
investigated.
Alan
next prev parent reply other threads:[~2012-11-21 12:47 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-16 19:27 [PATCH] fb: Rework locking to fix lock ordering on takeover Alan Cox
2012-11-21 12:45 ` Josh Boyer
2012-11-21 12:53 ` Alan Cox [this message]
2012-12-18 15:20 ` Josh Boyer
2012-12-25 16:08 ` Sasha Levin
2012-12-26 2:41 ` Cong Wang
2012-12-26 18:09 ` Sasha Levin
2012-12-27 4:53 ` Borislav Petkov
2012-12-28 11:50 ` Shawn Guo
2012-12-28 12:40 ` Borislav Petkov
2013-01-04 12:50 ` Alexander Holler
2013-01-04 13:25 ` Alan Cox
2013-01-04 13:36 ` Alexander Holler
2013-01-05 11:41 ` Alexander Holler
2013-01-05 11:42 ` [PATCH] fb: udlfb: fix scheduling while atomic Alexander Holler
2013-01-06 12:46 ` Alexander Holler
2013-01-09 13:47 ` [PATCH v2] " Alexander Holler
2013-01-05 12:07 ` [PATCH] fb: Rework locking to fix lock ordering on takeover Alan Cox
2013-01-05 12:06 ` Alexander Holler
2013-01-07 9:37 ` Jiri Kosina
2013-01-12 18:36 ` Borislav Petkov
2013-01-12 20:51 ` Linus Torvalds
2013-01-12 21:05 ` Alan Cox
2013-01-12 21:13 ` Andrew Morton
2013-01-13 0:02 ` Borislav Petkov
2013-01-15 12:06 ` Maarten Lankhorst
2013-01-15 15:12 ` Alan Cox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121121125310.00625f55@pyramind.ukuu.org.uk \
--to=alan@lxorguk.ukuu.org.uk \
--cc=florianschandinat@gmx.de \
--cc=jwboyer@gmail.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox