From: Victor Nogueira <victor@mojatatu.com> mainline inclusion from mainline-v6.18-rc6 commit e781122d76f018ad17752ab1018b3ffbf7fad84e category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/ID64WJ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Wang reported an illegal configuration [1] where the user attempts to add a child qdisc to the ingress qdisc as follows: tc qdisc add dev eth0 handle ffff:0 ingress tc qdisc add dev eth0 handle ffe0:0 parent ffff:a fq To solve this, we reject any configuration attempt to add a child qdisc to ingress or clsact. [1] https://lore.kernel.org/netdev/20251105022213.1981982-1-wangliang74@huawei.c... Fixes: 5e50da01d0ce ("[NET_SCHED]: Fix endless loops (part 2): "simple" qdiscs") Reported-by: Wang Liang <wangliang74@huawei.com> Closes: https://lore.kernel.org/netdev/20251105022213.1981982-1-wangliang74@huawei.c... Reviewed-by: Pedro Tammela <pctammela@mojatatu.ai> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Victor Nogueira <victor@mojatatu.com> Reviewed-by: Cong Wang <cwang@multikernel.io> Link: https://patch.msgid.link/20251106205621.3307639-1-victor@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Wang Liang <wangliang74@huawei.com> --- net/sched/sch_api.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 05bed30b0a6a..2ea9e7753cb0 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1492,6 +1492,11 @@ static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n, NL_SET_ERR_MSG(extack, "Failed to find specified qdisc"); return -ENOENT; } + if (p->flags & TCQ_F_INGRESS) { + NL_SET_ERR_MSG(extack, + "Cannot add children to ingress/clsact qdisc"); + return -EOPNOTSUPP; + } q = qdisc_leaf(p, clid, extack); if (IS_ERR(q)) return PTR_ERR(q); -- 2.34.1