At Wed, 23 Jan 2013 17:25:08 +0100,
Daniel Vetter wrote:
From: Alan Cox <redacted>
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 <redacted>
[danvet: Tiny whitespace cleanup.]
Reported-and-tested-by: Hugh Dickins <hughd@google.com>
Reported-and-tested-by: Sasha Levin <redacted>
References: https://lkml.org/lkml/2012/10/25/516
Signed-off-by: Daniel Vetter <redacted>
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