In the Linux kernel, the following vulnerability has been resolved: net: can: j1939: j1939xtprxrtssessionactive(): deactivate session upon receiving the second rts Since j1939sessiondeactivateactivatenext() in j1939tprxtimer() is called only when the timer is enabled, we need to call j1939sessiondeactivateactivatenext() if we cancelled the timer. Otherwise, refcount for j1939session leaks, which will later appear as | unregister_netdevice: waiting for vcan0 to become free. Usage count = 2. problem.