From c278850206fd9df0bb62a72ca0b277fe20c5a452 Mon Sep 17 00:00:00 2001 From: Simon Arlott Date: Sat, 10 Mar 2007 06:21:25 -0300 Subject: 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 Signed-off-by: Andrew Morton Acked-By: Johannes Stezenbach Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb/dvb-core/dvb_demux.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) (limited to 'drivers/media/dvb/dvb-core/dvb_demux.c') 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) struct dvb_demux *demux = feed->demux; int ret; - if (mutex_lock_interruptible(&demux->mutex)) - return -ERESTARTSYS; + mutex_lock(&demux->mutex); if (feed->state < DMX_STATE_GO) { mutex_unlock(&demux->mutex); @@ -748,8 +747,7 @@ static int dvbdmx_release_ts_feed(struct dmx_demux *dmx, struct dvb_demux *demux = (struct dvb_demux *)dmx; struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed; - if (mutex_lock_interruptible(&demux->mutex)) - return -ERESTARTSYS; + mutex_lock(&demux->mutex); if (feed->state == DMX_STATE_FREE) { mutex_unlock(&demux->mutex); @@ -916,8 +914,7 @@ static int dmx_section_feed_stop_filtering(struct dmx_section_feed *feed) struct dvb_demux *dvbdmx = dvbdmxfeed->demux; int ret; - if (mutex_lock_interruptible(&dvbdmx->mutex)) - return -ERESTARTSYS; + mutex_lock(&dvbdmx->mutex); if (!dvbdmx->stop_feed) { mutex_unlock(&dvbdmx->mutex); @@ -942,8 +939,7 @@ static int dmx_section_feed_release_filter(struct dmx_section_feed *feed, struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed; struct dvb_demux *dvbdmx = dvbdmxfeed->demux; - if (mutex_lock_interruptible(&dvbdmx->mutex)) - return -ERESTARTSYS; + mutex_lock(&dvbdmx->mutex); if (dvbdmxfilter->feed != dvbdmxfeed) { mutex_unlock(&dvbdmx->mutex); @@ -1016,8 +1012,7 @@ static int dvbdmx_release_section_feed(struct dmx_demux *demux, struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed; struct dvb_demux *dvbdmx = (struct dvb_demux *)demux; - if (mutex_lock_interruptible(&dvbdmx->mutex)) - return -ERESTARTSYS; + mutex_lock(&dvbdmx->mutex); if (dvbdmxfeed->state == DMX_STATE_FREE) { mutex_unlock(&dvbdmx->mutex); @@ -1126,8 +1121,7 @@ static int dvbdmx_connect_frontend(struct dmx_demux *demux, if (demux->frontend) return -EINVAL; - if (mutex_lock_interruptible(&dvbdemux->mutex)) - return -ERESTARTSYS; + mutex_lock(&dvbdemux->mutex); demux->frontend = frontend; mutex_unlock(&dvbdemux->mutex); @@ -1138,8 +1132,7 @@ static int dvbdmx_disconnect_frontend(struct dmx_demux *demux) { struct dvb_demux *dvbdemux = (struct dvb_demux *)demux; - if (mutex_lock_interruptible(&dvbdemux->mutex)) - return -ERESTARTSYS; + mutex_lock(&dvbdemux->mutex); demux->frontend = NULL; mutex_unlock(&dvbdemux->mutex); -- cgit v1.2.3