lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

V4L/DVB (11841): core: fix potential mutex_unlock without mutex_lock in dvb_dvr_read

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/media/dvb/dvb-core/dmxdev.c
View File

@@ -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 dvb_device *dvbdev = file->private_data;
struct dmxdev *dmxdev = dvbdev->priv; struct dmxdev *dmxdev = dvbdev->priv;
int ret;
if (dmxdev->exit) { if (dmxdev->exit)
mutex_unlock(&dmxdev->mutex);
return -ENODEV; return -ENODEV;
}
//mutex_lock(&dmxdev->mutex); return dvb_dmxdev_buffer_read(&dmxdev->dvr_buffer,
ret = dvb_dmxdev_buffer_read(&dmxdev->dvr_buffer, file->f_flags & O_NONBLOCK,
file->f_flags & O_NONBLOCK, buf, count, ppos);
buf, count, ppos);
//mutex_unlock(&dmxdev->mutex);
return ret;
} }
static int dvb_dvr_set_buffer_size(struct dmxdev *dmxdev, static int dvb_dvr_set_buffer_size(struct dmxdev *dmxdev,