media: mc: Clear minor number before put device

[ Upstream commit 8cfc8cec1b4da88a47c243a11f384baefd092a50 ]

The device minor should not be cleared after the device is released.

Fixes: 9e14868dc952 ("media: mc: Clear minor number reservation at unregistration time")
Cc: stable@vger.kernel.org
Reported-by: syzbot+031d0cfd7c362817963f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=031d0cfd7c362817963f
Tested-by: syzbot+031d0cfd7c362817963f@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
[ moved clear_bit from media_devnode_release callback to media_devnode_unregister before put_device ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
index f249199dc616b9e935d0056bc8cf81f1dd0f533d..f8257aa5fc5843bb2302fa509d1c79b56681d8e5 100644 (file)
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -50,11 +50,6 @@ static void media_devnode_release(struct device *cd)
 {
        struct media_devnode *devnode = to_media_devnode(cd);
 
-       mutex_lock(&media_devnode_lock);
-       /* Mark device node number as free */
-       clear_bit(devnode->minor, media_devnode_nums);
-       mutex_unlock(&media_devnode_lock);
-
        /* Release media_devnode and perform other cleanups as needed. */
        if (devnode->release)
                devnode->release(devnode);
@@ -283,6 +278,7 @@ void media_devnode_unregister(struct media_devnode *devnode)
        /* Delete the cdev on this minor as well */
        cdev_device_del(&devnode->cdev, &devnode->dev);
        devnode->media_dev = NULL;
+       clear_bit(devnode->minor, media_devnode_nums);
        mutex_unlock(&media_devnode_lock);
 
        put_device(&devnode->dev);