diff options
| author | Jonathan Nieder <jrnieder@gmail.com> | 2011-05-01 11:29:37 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-05-20 14:29:36 +0200 |
| commit | 1fe70e963028f34ba5e32488a7870ff4b410b19b (patch) | |
| tree | 8185ba45b69831b8cb6a1b1aef5cb84ea092b8cc /drivers/media/video/cx88/cx88-dvb.c | |
| parent | [media] cx88: protect per-device driver list with device lock (diff) | |
| download | linux-1fe70e963028f34ba5e32488a7870ff4b410b19b.tar.xz linux-1fe70e963028f34ba5e32488a7870ff4b410b19b.zip | |
[media] cx88: fix locking of sub-driver operations
The BKL conversion of this driver seems to have gone wrong.
Loading the cx88-blackbird driver deadlocks.
The cause: mpeg_ops::open in the cx2388x blackbird driver acquires the
device lock and calls the sub-driver's request_acquire, which tries to
acquire the lock again. Fix it by clarifying the semantics of
request_acquire, request_release, advise_acquire, and advise_release:
now all will rely on the caller to acquire the device lock.
Based on work by Ben Hutchings <ben@decadent.org.uk>.
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=31962
Reported-by: Andi Huber <hobrom@gmx.at>
Tested-by: Andi Huber <hobrom@gmx.at>
Tested-by: Marlon de Boer <marlon@hyves.nl>
Cc: stable@kernel.org
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/cx88/cx88-dvb.c')
| -rw-r--r-- | drivers/media/video/cx88/cx88-dvb.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/media/video/cx88/cx88-dvb.c b/drivers/media/video/cx88/cx88-dvb.c index 84002bc80db5..c69df7ebb6a7 100644 --- a/drivers/media/video/cx88/cx88-dvb.c +++ b/drivers/media/video/cx88/cx88-dvb.c @@ -135,8 +135,6 @@ static int cx88_dvb_bus_ctrl(struct dvb_frontend* fe, int acquire) mutex_lock(&dev->core->lock); drv = cx8802_get_driver(dev, CX88_MPEG_DVB); - mutex_unlock(&dev->core->lock); - if (drv) { if (acquire){ dev->frontends.active_fe_id = fe_id; @@ -146,6 +144,7 @@ static int cx88_dvb_bus_ctrl(struct dvb_frontend* fe, int acquire) dev->frontends.active_fe_id = 0; } } + mutex_unlock(&dev->core->lock); return ret; } |