Messages in this thread Patch in this message | | | Date | Thu, 23 Apr 2009 18:32:13 +0100 | From | Simon Arlott <> | Subject | [PATCH] dvb-core: Fix potential mutex_unlock without mutex_lock in dvb_dvr_read |
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dvb_dvr_read may unlock the dmxdev mutex and return -ENODEV, except this function is a file op and will never be called with the mutex held.
There's existing mutex_lock and mutex_unlock around the actual read but it's commented out. These should probably be uncommented but the read blocks and this could block another non-blocking reader on the mutex instead.
This change comments out the extra mutex_unlock.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu> --- This has been on my TODO list for far too long... I did come up with a mutex_trylock/mutex_lock_interruptible version but claiming that it'll block when it may not doesn't make sense (and any blocking read would cause all non-blocking reads to continually return -EWOULDBLOCK until there is data).
drivers/media/dvb/dvb-core/dmxdev.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/media/dvb/dvb-core/dmxdev.c b/drivers/media/dvb/dvb-core/dmxdev.c index c35fbb8..d6d098a 100644 --- a/drivers/media/dvb/dvb-core/dmxdev.c +++ b/drivers/media/dvb/dvb-core/dmxdev.c @@ -247,7 +247,7 @@ static ssize_t dvb_dvr_read(struct file *file, char __user *buf, size_t count, int ret; if (dmxdev->exit) { - mutex_unlock(&dmxdev->mutex); + //mutex_unlock(&dmxdev->mutex); return -ENODEV; } -- 1.6.2.2 -- Simon Arlott
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