kernel: kernel: net_sched: fix qdisc_notify()

The qdiscnotify function in net/sched/schapi.c in the Linux kernel before 2.6.35 does not prevent tcfillqdisc function calls referencing builtin aka CQFBUILTIN Qdisc structures, which allows local users to cause a denial of service NULL pointer dereference and OOPS or possibly have unspecified...