From: Cong Wang <xiyou.wangcong@gmail.com> mainline inclusion from mainline-v6.15-rc2 commit 55f9eca4bfe30a15d8656f915922e8c98b7f0728 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... -------------------------------- qfq_qlen_notify() always deletes its class from its active list with list_del_init() _and_ calls qfq_deactivate_agg() when the whole list becomes empty. To make it idempotent, just skip everything when it is not in the active list. Also change other list_del()'s to list_del_init() just to be extra safe. Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250403211033.166059-5-xiyou.wangcong@gmail.com Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Conflicts: net/sched/sch_qfq.c [commit 67c9e6270f30 is not backport] Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/sched/sch_qfq.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c index b07f396212c5..b6f9a8bc9e24 100644 --- a/net/sched/sch_qfq.c +++ b/net/sched/sch_qfq.c @@ -349,7 +349,7 @@ static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) struct qfq_aggregate *agg = cl->agg; - list_del(&cl->alist); /* remove from RR queue of the aggregate */ + list_del_init(&cl->alist); /* remove from RR queue of the aggregate */ if (list_empty(&agg->active)) /* agg is now inactive */ qfq_deactivate_agg(q, agg); } @@ -477,6 +477,7 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, cl->common.classid = classid; cl->deficit = lmax; + INIT_LIST_HEAD(&cl->alist); cl->qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid, NULL); @@ -990,7 +991,7 @@ static struct sk_buff *agg_dequeue(struct qfq_aggregate *agg, cl->deficit -= (int) len; if (cl->qdisc->q.qlen == 0) /* no more packets, remove from list */ - list_del(&cl->alist); + list_del_init(&cl->alist); else if (cl->deficit < qdisc_pkt_len(cl->qdisc->ops->peek(cl->qdisc))) { cl->deficit += agg->lmax; list_move_tail(&cl->alist, &agg->active); @@ -1424,6 +1425,8 @@ static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg) struct qfq_sched *q = qdisc_priv(sch); struct qfq_class *cl = (struct qfq_class *)arg; + if (list_empty(&cl->alist)) + return; qfq_deactivate_class(q, cl); } -- 2.25.1