kernel: net/sched: ets: Always remove class from active list before deleting in ets_qdisc_change

In the Linux kernel, the following vulnerability has been resolved: net/sched: ets: Always remove class from active list before deleting in etsqdiscchange [email protected] says: The vulnerability is a race condition between etsqdiscdequeue and etsqdiscchange. It leads to UAF on stru...