From: Alexey Khoroshilov <khoroshilov@ispras.ru>
Date: Sat, 9 Nov 2013 21:28:43 +0000 (-0300)
Subject: [media] dvb_demux: fix deadlock in dmx_section_feed_release_filter()
X-Git-Tag: v3.13-rc4~25^2~26
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6633327d59067fe16128d66968cd50a10ca7a09c;p=pandora-kernel.git

[media] dvb_demux: fix deadlock in dmx_section_feed_release_filter()

dmx_section_feed_release_filter() locks dvbdmx->mutex and
if the feed is still filtering, it calls feed->stop_filtering(feed).
stop_filtering() is implemented by dmx_section_feed_stop_filtering()
that first of all try to lock the same mutex: dvbdmx->mutex.
That leads to a deadlock.
It does not happen often in practice because all callers of
release_filter() stop filtering by themselves.
So the problem can happen in case of race condition only.
The patch releases dvbdmx->mutex before call to feed->stop_filtering(feed)
and reacquires the mutex after that.
Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---

Reading git-diff-tree failed