[media] em28xx: fix deadlock when unplugging and replugging a DVB adapter

This fixes the deadlock that occurs with either multiple PCTV 290e adapters or when a single PCTV 290e adapter is replugged.

For DVB devices, the device lock must now *not* be held when adding/removing either a device or an extension to the respective lists. (Because em28xx_init_dvb() will want to take the lock instead).

Conversely, for Audio-Only devices, the device lock *must* be held when adding/removing either a device or an extension to the respective lists.

Signed-off-by: Chris Rankin <rankincj@yahoo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
index 7297d90..2e1c121 100644 (file)
--- a/drivers/media/video/em28xx/em28xx-cards.c
+++ b/drivers/media/video/em28xx/em28xx-cards.c
@@ -3005,7 +3005,9 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
                goto fail;
        }
 
+       mutex_unlock(&dev->lock);
        em28xx_init_extension(dev);
+       mutex_lock(&dev->lock);
 
        /* Save some power by putting tuner to sleep */
        v4l2_device_call_all(&dev->v4l2_dev, 0, core, s_power, 0);
@@ -3301,10 +3303,10 @@ static void em28xx_usb_disconnect(struct usb_interface *interface)
                em28xx_release_resources(dev);
        }
 
-       em28xx_close_extension(dev);
-
        mutex_unlock(&dev->lock);
 
+       em28xx_close_extension(dev);
+
        if (!dev->users) {
                kfree(dev->alt_max_pkt_size);
                kfree(dev);