From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH 1/2] fb: Rework locking to fix lock ordering on takeover Date: Wed, 23 Jan 2013 17:38:42 +0100 Message-ID: References: <1358958309-5342-1-git-send-email-daniel.vetter@ffwll.ch> <1358958309-5342-2-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <1358958309-5342-2-git-send-email-daniel.vetter@ffwll.ch> Sender: linux-kernel-owner@vger.kernel.org To: Daniel Vetter Cc: Dave Airlie , Intel Graphics Development , DRI Development , LKML , linux-fbdev-devel@lists.sourceforge.net, Alan Cox , Alan Cox List-Id: intel-gfx@lists.freedesktop.org At Wed, 23 Jan 2013 17:25:08 +0100, Daniel Vetter wrote: > > From: Alan Cox > > 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 > [danvet: Tiny whitespace cleanup.] > Reported-and-tested-by: Hugh Dickins > Reported-and-tested-by: Sasha Levin > References: https://lkml.org/lkml/2012/10/25/516 > Signed-off-by: Daniel Vetter FYI, the latest patch of this is found in mm tree: http://ozlabs.org/~akpm/mmots/broken-out/fb-rework-locking-to-fix-lock-ordering-on-takeover.patch Also I hit the same problem in another code paths (for unbind and unregister): http://marc.info/?t=135309396400003&r=1&w=2 My additional patch is found in mm tree, too: http://ozlabs.org/~akpm/mmots/broken-out/fb-yet-another-band-aid-for-fixing-lockdep-mess.patch Takashi