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V4L/DVB (11841): 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.

[akpm@linux-foundation.org: cleanups, simplification]
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Simon Arlott 2009-05-12 17:39:28 -03:00 committed by Mauro Carvalho Chehab
parent 1010ed1327
commit eda9f7523b
1 changed files with 4 additions and 10 deletions
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14
drivers/media/dvb/dvb-core/dmxdev.c
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@ -244,19 +244,13 @@ static ssize_t dvb_dvr_read(struct file *file, char __user *buf, size_t count,
{
struct dvb_device *dvbdev = file->private_data;
struct dmxdev *dmxdev = dvbdev->priv;
int ret;
if (dmxdev->exit) {
mutex_unlock(&dmxdev->mutex);
if (dmxdev->exit)
return -ENODEV;
}
//mutex_lock(&dmxdev->mutex);
ret = dvb_dmxdev_buffer_read(&dmxdev->dvr_buffer,
file->f_flags & O_NONBLOCK,
buf, count, ppos);
//mutex_unlock(&dmxdev->mutex);
return ret;
return dvb_dmxdev_buffer_read(&dmxdev->dvr_buffer,
file->f_flags & O_NONBLOCK,
buf, count, ppos);
}
static int dvb_dvr_set_buffer_size(struct dmxdev *dmxdev,