linux/net/sched
Cong Wang c2d25fddd8 sch_htb: make htb_deactivate() idempotent
commit 3769478610 upstream.

Alan reported a NULL pointer dereference in htb_next_rb_node()
after we made htb_qlen_notify() idempotent.

It turns out in the following case it introduced some regression:

htb_dequeue_tree():
  |-> fq_codel_dequeue()
    |-> qdisc_tree_reduce_backlog()
      |-> htb_qlen_notify()
        |-> htb_deactivate()
  |-> htb_next_rb_node()
  |-> htb_deactivate()

For htb_next_rb_node(), after calling the 1st htb_deactivate(), the
clprio[prio]->ptr could be already set to  NULL, which means
htb_next_rb_node() is vulnerable here.

For htb_deactivate(), although we checked qlen before calling it, in
case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again
which triggers the warning inside.

To fix the issues here, we need to:

1) Make htb_deactivate() idempotent, that is, simply return if we
   already call it before.
2) Make htb_next_rb_node() safe against ptr==NULL.

Many thanks to Alan for testing and for the reproducer.

Fixes: 5ba8b837b5 ("sch_htb: make htb_qlen_notify() idempotent")
Reported-by: Alan J. Wylie <alan@wylie.me.uk>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://patch.msgid.link/20250428232955.1740419-2-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Siddh Raman Pant <siddh.raman.pant@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-08-28 16:24:33 +02:00
..
act_api.c net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc() 2024-07-05 09:14:30 +02:00
act_bpf.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_connmark.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_csum.c net_sched: refactor TC action init API 2021-08-02 10:24:38 +01:00
act_ct.c sched: act_ct: take care of padding in struct zones_ht_key 2024-08-19 05:45:31 +02:00
act_ctinfo.c net_sched: act_ctinfo: use atomic64_t for three counters 2025-08-28 16:24:08 +02:00
act_gact.c net_sched: refactor TC action init API 2021-08-02 10:24:38 +01:00
act_gate.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_ife.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_ipt.c net/sched: act_ipt: add sanity checks on table name and hook locations 2023-07-23 13:47:28 +02:00
act_meta_mark.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
act_meta_skbprio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
act_meta_skbtcindex.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
act_mirred.c net/sched: act_mirred: don't override retval if we already lost the skb 2025-05-09 09:39:37 +02:00
act_mpls.c net/sched: act_mpls: fix action bind logic 2023-03-11 13:57:30 +01:00
act_nat.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_pedit.c net/sched: act_pedit: Add size check for TCA_PEDIT_PARMS_EX 2023-07-23 13:47:29 +02:00
act_police.c net: sched: act_police: fix sparse errors in tcf_police_dump() 2023-06-14 11:13:03 +02:00
act_sample.c net/sched: act_sample: fix action bind logic 2023-03-11 13:57:30 +01:00
act_simple.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_skbedit.c flow_offload: fill flags to action structure 2023-02-22 12:57:10 +01:00
act_skbmod.c net/sched: act_skbmod: prevent kernel-infoleak 2024-04-10 16:19:38 +02:00
act_tunnel_key.c net: fix geneve_opt length integer overflow 2025-04-10 14:32:05 +02:00
act_vlan.c net_sched: refactor TC action init API 2021-08-02 10:24:38 +01:00
cls_api.c net/sched: cls_api: Fix lockup on flushing explicitly created chain 2023-06-21 15:59:18 +02:00
cls_basic.c net_sched: refactor TC action init API 2021-08-02 10:24:38 +01:00
cls_bpf.c net: sched: cls_bpf: Undo tcf_bind_filter in case of an error 2023-07-27 08:47:00 +02:00
cls_cgroup.c net_sched: refactor TC action init API 2021-08-02 10:24:38 +01:00
cls_flow.c net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute 2025-01-23 17:15:49 +01:00
cls_flower.c net: fix geneve_opt length integer overflow 2025-04-10 14:32:05 +02:00
cls_fw.c net/sched: cls_fw: No longer copy tcf_result on update to avoid use-after-free 2023-08-11 15:13:52 +02:00
cls_matchall.c net_sched: refactor TC action init API 2021-08-02 10:24:38 +01:00
cls_route.c net/sched: cls_route: No longer copy tcf_result on update to avoid use-after-free 2023-08-11 15:13:52 +02:00
cls_u32.c net: sched: cls_u32: Fix allocation size in u32_init() 2023-11-08 17:26:45 +01:00
em_canid.c net: sched: kerneldoc fixes 2020-07-13 17:20:40 -07:00
em_cmp.c net: sched: fix misspellings using misspell-fixer tool 2020-11-10 17:00:28 -08:00
em_ipset.c sched: consistently handle layer3 header accesses in the presence of VLANs 2020-07-03 14:34:53 -07:00
em_ipt.c sched: consistently handle layer3 header accesses in the presence of VLANs 2020-07-03 14:34:53 -07:00
em_meta.c sched: consistently handle layer3 header accesses in the presence of VLANs 2020-07-03 14:34:53 -07:00
em_nbyte.c net: sched: Return the correct errno code 2021-02-06 11:15:28 -08:00
em_text.c net: sched: em_text: fix possible memory leak in em_text_destroy() 2024-01-15 18:51:12 +01:00
em_u32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ematch.c net_sched: reject TCF_EM_SIMPLE case for complex ematch module 2022-12-31 13:14:39 +01:00
Kconfig net/sched: Retire dsmark qdisc 2024-03-01 13:21:42 +01:00
Makefile net/sched: Retire dsmark qdisc 2024-03-01 13:21:42 +01:00
sch_api.c net/sched: Abort __tc_modify_qdisc if parent class does not exist 2025-07-17 18:30:47 +02:00
sch_blackhole.c Revert "net: sched: Pass root lock to Qdisc_ops.enqueue" 2020-07-16 16:48:34 -07:00
sch_cake.c sched: sch_cake: add bounds checks to host bulk flow fairness counts 2025-03-13 12:51:12 +01:00
sch_cbs.c net/sched: cbs: Fix integer overflow in cbs_set_port_rate() 2024-12-14 19:51:36 +01:00
sch_choke.c net: sched: fix ordering of qlen adjustment 2025-01-09 13:28:29 +01:00
sch_codel.c codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog() 2025-08-28 16:24:33 +02:00
sch_drr.c sch_drr: make drr_qlen_notify() idempotent 2025-08-28 16:24:33 +02:00
sch_etf.c net: sched: delete duplicate cleanup of backlog and qlen 2022-10-29 10:12:57 +02:00
sch_ets.c net/sched: ets: use old 'nbands' while purging unused classes 2025-08-28 16:24:32 +02:00
sch_fifo.c pfifo_tail_enqueue: Drop new packet when sch->limit == 0 2025-03-13 12:51:00 +01:00
sch_fq.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:08:22 +02:00
sch_fq_codel.c codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog() 2025-08-28 16:24:33 +02:00
sch_fq_pie.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:08:22 +02:00
sch_frag.c net/sched: Extend qdisc control block with tc control block 2022-01-05 12:42:33 +01:00
sch_generic.c net/sched: fix netdevice reference leaks in attach_default_qdiscs() 2022-09-08 12:28:02 +02:00
sch_gred.c net: sched: Fix spelling mistakes 2021-05-31 22:44:56 -07:00
sch_hfsc.c sch_hfsc: make hfsc_qlen_notify() idempotent 2025-08-28 16:24:30 +02:00
sch_hhf.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:08:22 +02:00
sch_htb.c sch_htb: make htb_deactivate() idempotent 2025-08-28 16:24:33 +02:00
sch_ingress.c net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact) Qdiscs 2023-06-09 10:32:17 +02:00
sch_mq.c net: sched: update default qdisc visibility after Tx queue cnt changes 2021-11-18 19:16:10 +01:00
sch_mqprio.c net/sched: mqprio: Add length check for TCA_MQPRIO_{MAX/MIN}_RATE64 2023-08-03 10:22:36 +02:00
sch_multiq.c net: sched: sch_multiq: fix possible OOB write in multiq_tune() 2024-07-05 09:14:06 +02:00
sch_netem.c net/sched: Restrict conditions for adding duplicating netems to qdisc tree 2025-08-28 16:24:08 +02:00
sch_pie.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:08:22 +02:00
sch_plug.c net: sched: sch_qfq: Fix UAF in qfq_dequeue() 2023-09-19 12:22:59 +02:00
sch_prio.c net_sched: prio: fix a race in prio_tune() 2025-06-27 11:05:20 +01:00
sch_qfq.c sch_qfq: make qfq_qlen_notify() idempotent 2025-08-28 16:24:30 +02:00
sch_red.c net_sched: red: fix a race in __red_change() 2025-06-27 11:05:20 +01:00
sch_sfb.c net: sched: sfb: fix null pointer access issue when sfb_init() fails 2022-10-29 10:12:57 +02:00
sch_sfq.c net_sched: sch_sfq: reject invalid perturb period 2025-06-27 11:05:37 +01:00
sch_skbprio.c net_sched: skbprio: Remove overly strict queue assertions 2025-04-10 14:32:04 +02:00
sch_taprio.c net: sched: fix use-after-free in taprio_change() 2024-11-01 01:52:37 +01:00
sch_tbf.c net_sched: tbf: fix a race in tbf_change() 2025-06-27 11:05:20 +01:00
sch_teql.c net: sched: delete duplicate cleanup of backlog and qlen 2022-10-29 10:12:57 +02:00