diff options
author | Simon Arlott <simon@fire.lp0.eu> | 2007-03-10 04:21:25 -0500 |
---|---|---|
committer | Mauro Carvalho Chehab <mchehab@infradead.org> | 2007-03-27 07:45:54 -0400 |
commit | c278850206fd9df0bb62a72ca0b277fe20c5a452 (patch) | |
tree | 439ae68737b5bcb5d473b3d12c3d5417f697ccb3 /drivers/media/dvb/dvb-core/dvb_demux.c | |
parent | b10fece583fdfdb3d2f29b0da3896ec58b8fe122 (diff) |
V4L/DVB (5400): Core: fix several locking related problems
Fix several instances of dvb-core functions using mutex_lock_interruptible
and returning -ERESTARTSYS where the calling function will either never
retry or never check the return value.
These cause a race condition with dvb_dmxdev_filter_free and
dvb_dvr_release, both of which are filesystem release functions whose
return value is ignored and will never be retried. When this happens it
becomes impossible to open dvr0 again (-EBUSY) since it has not been
released properly.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-By: Johannes Stezenbach <js@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Diffstat (limited to 'drivers/media/dvb/dvb-core/dvb_demux.c')
-rw-r--r-- | drivers/media/dvb/dvb-core/dvb_demux.c | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_demux.c b/drivers/media/dvb/dvb-core/dvb_demux.c index fcff5eab21a..6d8d1c3df86 100644 --- a/drivers/media/dvb/dvb-core/dvb_demux.c +++ b/drivers/media/dvb/dvb-core/dvb_demux.c | |||
@@ -673,8 +673,7 @@ static int dmx_ts_feed_stop_filtering(struct dmx_ts_feed *ts_feed) | |||
673 | struct dvb_demux *demux = feed->demux; | 673 | struct dvb_demux *demux = feed->demux; |
674 | int ret; | 674 | int ret; |
675 | 675 | ||
676 | if (mutex_lock_interruptible(&demux->mutex)) | 676 | mutex_lock(&demux->mutex); |
677 | return -ERESTARTSYS; | ||
678 | 677 | ||
679 | if (feed->state < DMX_STATE_GO) { | 678 | if (feed->state < DMX_STATE_GO) { |
680 | mutex_unlock(&demux->mutex); | 679 | mutex_unlock(&demux->mutex); |
@@ -748,8 +747,7 @@ static int dvbdmx_release_ts_feed(struct dmx_demux *dmx, | |||
748 | struct dvb_demux *demux = (struct dvb_demux *)dmx; | 747 | struct dvb_demux *demux = (struct dvb_demux *)dmx; |
749 | struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed; | 748 | struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed; |
750 | 749 | ||
751 | if (mutex_lock_interruptible(&demux->mutex)) | 750 | mutex_lock(&demux->mutex); |
752 | return -ERESTARTSYS; | ||
753 | 751 | ||
754 | if (feed->state == DMX_STATE_FREE) { | 752 | if (feed->state == DMX_STATE_FREE) { |
755 | mutex_unlock(&demux->mutex); | 753 | mutex_unlock(&demux->mutex); |
@@ -916,8 +914,7 @@ static int dmx_section_feed_stop_filtering(struct dmx_section_feed *feed) | |||
916 | struct dvb_demux *dvbdmx = dvbdmxfeed->demux; | 914 | struct dvb_demux *dvbdmx = dvbdmxfeed->demux; |
917 | int ret; | 915 | int ret; |
918 | 916 | ||
919 | if (mutex_lock_interruptible(&dvbdmx->mutex)) | 917 | mutex_lock(&dvbdmx->mutex); |
920 | return -ERESTARTSYS; | ||
921 | 918 | ||
922 | if (!dvbdmx->stop_feed) { | 919 | if (!dvbdmx->stop_feed) { |
923 | mutex_unlock(&dvbdmx->mutex); | 920 | mutex_unlock(&dvbdmx->mutex); |
@@ -942,8 +939,7 @@ static int dmx_section_feed_release_filter(struct dmx_section_feed *feed, | |||
942 | struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed; | 939 | struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed; |
943 | struct dvb_demux *dvbdmx = dvbdmxfeed->demux; | 940 | struct dvb_demux *dvbdmx = dvbdmxfeed->demux; |
944 | 941 | ||
945 | if (mutex_lock_interruptible(&dvbdmx->mutex)) | 942 | mutex_lock(&dvbdmx->mutex); |
946 | return -ERESTARTSYS; | ||
947 | 943 | ||
948 | if (dvbdmxfilter->feed != dvbdmxfeed) { | 944 | if (dvbdmxfilter->feed != dvbdmxfeed) { |
949 | mutex_unlock(&dvbdmx->mutex); | 945 | mutex_unlock(&dvbdmx->mutex); |
@@ -1016,8 +1012,7 @@ static int dvbdmx_release_section_feed(struct dmx_demux *demux, | |||
1016 | struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed; | 1012 | struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed; |
1017 | struct dvb_demux *dvbdmx = (struct dvb_demux *)demux; | 1013 | struct dvb_demux *dvbdmx = (struct dvb_demux *)demux; |
1018 | 1014 | ||
1019 | if (mutex_lock_interruptible(&dvbdmx->mutex)) | 1015 | mutex_lock(&dvbdmx->mutex); |
1020 | return -ERESTARTSYS; | ||
1021 | 1016 | ||
1022 | if (dvbdmxfeed->state == DMX_STATE_FREE) { | 1017 | if (dvbdmxfeed->state == DMX_STATE_FREE) { |
1023 | mutex_unlock(&dvbdmx->mutex); | 1018 | mutex_unlock(&dvbdmx->mutex); |
@@ -1126,8 +1121,7 @@ static int dvbdmx_connect_frontend(struct dmx_demux *demux, | |||
1126 | if (demux->frontend) | 1121 | if (demux->frontend) |
1127 | return -EINVAL; | 1122 | return -EINVAL; |
1128 | 1123 | ||
1129 | if (mutex_lock_interruptible(&dvbdemux->mutex)) | 1124 | mutex_lock(&dvbdemux->mutex); |
1130 | return -ERESTARTSYS; | ||
1131 | 1125 | ||
1132 | demux->frontend = frontend; | 1126 | demux->frontend = frontend; |
1133 | mutex_unlock(&dvbdemux->mutex); | 1127 | mutex_unlock(&dvbdemux->mutex); |
@@ -1138,8 +1132,7 @@ static int dvbdmx_disconnect_frontend(struct dmx_demux *demux) | |||
1138 | { | 1132 | { |
1139 | struct dvb_demux *dvbdemux = (struct dvb_demux *)demux; | 1133 | struct dvb_demux *dvbdemux = (struct dvb_demux *)demux; |
1140 | 1134 | ||
1141 | if (mutex_lock_interruptible(&dvbdemux->mutex)) | 1135 | mutex_lock(&dvbdemux->mutex); |
1142 | return -ERESTARTSYS; | ||
1143 | 1136 | ||
1144 | demux->frontend = NULL; | 1137 | demux->frontend = NULL; |
1145 | mutex_unlock(&dvbdemux->mutex); | 1138 | mutex_unlock(&dvbdemux->mutex); |