At Wed, 23 Jan 2013 17:25:08 +0100,
Daniel Vetter wrote:
>
> From: Alan Cox <al...@lx...>
>
> 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 <al...@li...>
> [danvet: Tiny whitespace cleanup.]
> Reported-and-tested-by: Hugh Dickins <hu...@go...>
> Reported-and-tested-by: Sasha Levin <lev...@gm...>
> References: https://lkml.org/lkml/2012/10/25/516
> Signed-off-by: Daniel Vetter <dan...@ff...>
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
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