codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog()
[ Upstream commit 342debc12183b51773b3345ba267e9263bdfaaef ]
After making all ->qlen_notify() callbacks idempotent, now it is safe to
remove the check of qlen!=0 from both fq_codel_dequeue() and
codel_qdisc_dequeue().
BUG=b/410450423
TEST=presubmit
RELEASE_NOTE=Fixed KCTF-342debc in the Linux kernel.
cos-patch: security-high
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Fixes: 4b549a2ef4be ("fq_codel: Fair Queue Codel AQM")
Fixes: 76e3cc126bb2 ("codel: Controlled Delay AQM")
Change-Id: I99bacc60f4819c3c5908c153cffb7e7b82355fe4
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250403211636.166257-1-xiyou.wangcong@gmail.com
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/101102
Reviewed-by: Michael Kochera <kochera@google.com>
Reviewed-by: Anil Altinay <aaltinay@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c
index d7a4874..5f2e068 100644
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -95,10 +95,7 @@ static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch)
&q->stats, qdisc_pkt_len, codel_get_enqueue_time,
drop_func, dequeue_func);
- /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
- * or HTB crashes. Defer it for next round.
- */
- if (q->stats.drop_count && sch->q.qlen) {
+ if (q->stats.drop_count) {
qdisc_tree_reduce_backlog(sch, q->stats.drop_count, q->stats.drop_len);
q->stats.drop_count = 0;
q->stats.drop_len = 0;
diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index 8c4fee0..9330923 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -314,10 +314,8 @@ static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
}
qdisc_bstats_update(sch, skb);
flow->deficit -= qdisc_pkt_len(skb);
- /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
- * or HTB crashes. Defer it for next round.
- */
- if (q->cstats.drop_count && sch->q.qlen) {
+
+ if (q->cstats.drop_count) {
qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
q->cstats.drop_len);
q->cstats.drop_count = 0;
