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authorSimon Arlott <simon@fire.lp0.eu>2007-03-28 21:22:40 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-04-06 03:43:16 -0700
commit5e37b8eb6d8f4caa1150a1f3666e08f69798ed31 (patch)
tree51ccf1bf0381df709429c76b232e96146417a958
parent69e329bf0268ac4ac74e87636b1c745373d4ed65 (diff)
downloadlinux-linaro-stable-5e37b8eb6d8f4caa1150a1f3666e08f69798ed31.tar.gz
dvb-core: fix several locking related problems
dvb-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. (cherry picked from commit c278850206fd9df0bb62a72ca0b277fe20c5a452) 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> Signed-off-by: Michael Krufky <mkrufky@linuxtv.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/media/dvb/dvb-core/dmxdev.c12
-rw-r--r--drivers/media/dvb/dvb-core/dvb_demux.c21
-rw-r--r--drivers/media/dvb/dvb-core/dvbdev.c9
3 files changed, 13 insertions, 29 deletions
diff --git a/drivers/media/dvb/dvb-core/dmxdev.c b/drivers/media/dvb/dvb-core/dmxdev.c
index 988499dfddf8..ec473ebb327c 100644
--- a/drivers/media/dvb/dvb-core/dmxdev.c
+++ b/drivers/media/dvb/dvb-core/dmxdev.c
@@ -181,8 +181,7 @@ static int dvb_dvr_release(struct inode *inode, struct file *file)
struct dvb_device *dvbdev = file->private_data;
struct dmxdev *dmxdev = dvbdev->priv;
- if (mutex_lock_interruptible(&dmxdev->mutex))
- return -ERESTARTSYS;
+ mutex_lock(&dmxdev->mutex);
if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
dmxdev->demux->disconnect_frontend(dmxdev->demux);
@@ -674,13 +673,8 @@ static int dvb_demux_open(struct inode *inode, struct file *file)
static int dvb_dmxdev_filter_free(struct dmxdev *dmxdev,
struct dmxdev_filter *dmxdevfilter)
{
- if (mutex_lock_interruptible(&dmxdev->mutex))
- return -ERESTARTSYS;
-
- if (mutex_lock_interruptible(&dmxdevfilter->mutex)) {
- mutex_unlock(&dmxdev->mutex);
- return -ERESTARTSYS;
- }
+ mutex_lock(&dmxdev->mutex);
+ mutex_lock(&dmxdevfilter->mutex);
dvb_dmxdev_filter_stop(dmxdevfilter);
dvb_dmxdev_filter_reset(dmxdevfilter);
diff --git a/drivers/media/dvb/dvb-core/dvb_demux.c b/drivers/media/dvb/dvb-core/dvb_demux.c
index fcff5eab21a3..6d8d1c3df863 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);
diff --git a/drivers/media/dvb/dvb-core/dvbdev.c b/drivers/media/dvb/dvb-core/dvbdev.c
index af35f3058d0f..b3a8cbbda621 100644
--- a/drivers/media/dvb/dvb-core/dvbdev.c
+++ b/drivers/media/dvb/dvb-core/dvbdev.c
@@ -204,8 +204,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
int id;
- if (mutex_lock_interruptible(&dvbdev_register_lock))
- return -ERESTARTSYS;
+ mutex_lock(&dvbdev_register_lock);
if ((id = dvbdev_get_free_id (adap, type)) < 0) {
mutex_unlock(&dvbdev_register_lock);
@@ -295,8 +294,7 @@ int dvb_register_adapter(struct dvb_adapter *adap, const char *name, struct modu
{
int num;
- if (mutex_lock_interruptible(&dvbdev_register_lock))
- return -ERESTARTSYS;
+ mutex_lock(&dvbdev_register_lock);
if ((num = dvbdev_get_free_adapter_num ()) < 0) {
mutex_unlock(&dvbdev_register_lock);
@@ -324,8 +322,7 @@ EXPORT_SYMBOL(dvb_register_adapter);
int dvb_unregister_adapter(struct dvb_adapter *adap)
{
- if (mutex_lock_interruptible(&dvbdev_register_lock))
- return -ERESTARTSYS;
+ mutex_lock(&dvbdev_register_lock);
list_del (&adap->list_head);
mutex_unlock(&dvbdev_register_lock);
return 0;