commit a9b054e8 upstream.

Since we know that locking is broken in that case and it's more
important to not flood the dmesg with random gunk.
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
References: http://lkml.kernel.org/r/20130502000206.GH15623@pd.tnic
Cc: Dave Airlie <airlied@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>