usbnet: increase URB reference count before usb_unlink_urb

Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid
recursive locking in usbnet_stop()) fixes the recursive locking
problem by releasing the skb queue lock, but it makes usb_unlink_urb
racing with defer_bh, and the URB to being unlinked may be freed before
or during calling usb_unlink_urb, so use-after-free problem may be
triggerd inside usb_unlink_urb.

The patch fixes the use-after-free problem by increasing URB
reference count with skb queue lock held before calling
usb_unlink_urb, so the URB won't be freed until return from
usb_unlink_urb.

Cc: [email protected]
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: Oliver Neukum <[email protected]>
Reported-by: Dave Jones <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions