net/sched: sch_qfq: Fix race condition on qfq_aggregate

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: Fix race condition on qfq_aggregate A race condition can occur when 'agg' is modified in qfq_change_agg (called during qfq_enqueue) while other threads access it concurrently. For example, qfq_dump_class may trigger a NULL dereference, and qfq_delete_class may cause a use-after-free. This patch addresses the issue by: 1. Moved qfq_destroy_class into the critical section. 2. Added sch_tree_lock protection to qfq_dump_class and qfq_dump_class_stats.

References

• https://git.kernel.org/stable/c/aa7a22c4d678bf649fd3a1d27debec583563414d
• https://git.kernel.org/stable/c/d841aa5518508ab195b6781ad0d73ee378d713dd
• https://git.kernel.org/stable/c/c6df794000147a3a02f79984aada4ce83f8d0a1e
• https://git.kernel.org/stable/c/466e10194ab81caa2ee6a332d33ba16bcceeeba6
• https://git.kernel.org/stable/c/fbe48f06e64134dfeafa89ad23387f66ebca3527
• https://git.kernel.org/stable/c/a6d735100f602c830c16d69fb6d780eebd8c9ae1
• https://git.kernel.org/stable/c/c000a3a330d97f6c073ace5aa5faf94b9adb4b79
• https://git.kernel.org/stable/c/5e28d5a3f774f118896aec17a3a20a9c5c9dfc64