kernel: net/sched: fix lockdep splat in qdisc_tree_reduce_backlog()

CVE-2024-35892 is a vulnerability in the Linux kernel’s network scheduler caused by improper use of the qdisclookup function. This function assumes the global RTNL lock is held, but in the qdisctreereducebacklog function, only a local queue lock is used. This mismatch creates a race condition tha...