In the Linux kernel, the following vulnerability has been resolved:
net/sched: qfq: Use cl_is_active to determine whether class is active in qfq_rm_from_ag
This is more of a preventive patch to make the code more consistent and
to prevent possible exploits that employ child qlen manipulations on qfq.
use cl_is_active instead of relying on the child qdisc's qlen to determine
class activation.
References 4
https://git.kernel.org/stable/c/77f1afd0bb4d5da95236f6114e6d0dfcde187ff6
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/93b8635974fb050c43d07e35e5edfe6e685ca28a
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/abd9fc26ea577561a5ef6241a1b058755ffdad0c
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/d837fbee92453fbb829f950c8e7cf76207d73f33
416baaa9-dc9f-4396-8d5f-8c081fb06d67