From: Cong Wang <xiyou.wangcong@gmail.com> mainline inclusion from mainline-v6.15-rc2 commit 342debc12183b51773b3345ba267e9263bdfaaef category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC5D94 CVE: CVE-2025-37798 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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(). Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg> Fixes: 4b549a2ef4be ("fq_codel: Fair Queue Codel AQM") Fixes: 76e3cc126bb2 ("codel: Controlled Delay AQM") 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: Dong Chenchen <dongchenchen2@huawei.com> --- net/sched/sch_codel.c | 5 +---- net/sched/sch_fq_codel.c | 6 ++---- 2 files changed, 3 insertions(+), 8 deletions(-) diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c index 30169b3adbbb..d9eff03deada 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 01d6eea5b0ce..6adea8e7f153 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; -- 2.25.1