linux/net/sched
Kuniyuki Iwashima b8a7826e4b net: sched: Don't use WARN_ON_ONCE() for -ENOMEM in tcf_classify().
As demonstrated by syzbot, WARN_ON_ONCE() in tcf_classify() can
be easily triggered by fault injection. [0]

We should not use WARN_ON_ONCE() for the simple -ENOMEM case.

Also, we provide SKB_DROP_REASON_NOMEM for the same error.

Let's remove WARN_ON_ONCE() there.

[0]:
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 0 UID: 0 PID: 31392 Comm: syz.8.7081 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 should_fail_ex+0x414/0x560
 should_failslab+0xa8/0x100
 kmem_cache_alloc_noprof+0x74/0x6e0
 skb_ext_add+0x148/0x8f0
 tcf_classify+0xeba/0x1140
 multiq_enqueue+0xfd/0x4c0 net/sched/sch_multiq.c:66
...
WARNING: CPU: 0 PID: 31392 at net/sched/cls_api.c:1869 tcf_classify+0xfd7/0x1140
Modules linked in:
CPU: 0 UID: 0 PID: 31392 Comm: syz.8.7081 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:tcf_classify+0xfd7/0x1140
Code: e8 03 42 0f b6 04 30 84 c0 0f 85 41 01 00 00 66 41 89 1f eb 05 e8 89 26 75 f8 bb ff ff ff ff e9 04 f9 ff ff e8 7a 26 75 f8 90 <0f> 0b 90 49 83 c5 44 4c 89 eb 49 c1 ed 03 43 0f b6 44 35 00 84 c0
RSP: 0018:ffffc9000b7671f0 EFLAGS: 00010293
RAX: ffffffff894addf6 RBX: 0000000000000002 RCX: ffff888025029e40
RDX: 0000000000000000 RSI: ffffffff8bbf05c0 RDI: ffffffff8bbf0580
RBP: 0000000000000000 R08: 00000000ffffffff R09: 1ffffffff1c0bfd6
R10: dffffc0000000000 R11: fffffbfff1c0bfd7 R12: ffff88805a90de5c
R13: ffff88805a90ddc0 R14: dffffc0000000000 R15: ffffc9000b7672c0
FS:  00007f20739f66c0(0000) GS:ffff88812613e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2d2a80 CR3: 0000000024e36000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 multiq_classify net/sched/sch_multiq.c:39 [inline]
 multiq_enqueue+0xfd/0x4c0 net/sched/sch_multiq.c:66
 dev_qdisc_enqueue+0x4e/0x260 net/core/dev.c:4118
 __dev_xmit_skb net/core/dev.c:4214 [inline]
 __dev_queue_xmit+0xe83/0x3b50 net/core/dev.c:4729
 packet_snd net/packet/af_packet.c:3076 [inline]
 packet_sendmsg+0x3e33/0x5080 net/packet/af_packet.c:3108
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x830 net/socket.c:2630
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f207578efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f20739f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f20759e5fa0 RCX: 00007f207578efc9
RDX: 0000000000000004 RSI: 00002000000000c0 RDI: 0000000000000008
RBP: 00007f20739f6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f20759e6038 R14: 00007f20759e5fa0 R15: 00007f2075b0fa28
 </TASK>

Reported-by: syzbot+87e1289a044fcd0c5f62@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/69003e33.050a0220.32483.00e8.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20251028035859.2067690-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
History 2025-10-29 18:00:37 -07:00
..
act_api.c net_sched: act: remove tcfa_qstats 2025-09-02 15:52:24 -07:00
act_bpf.c net: Rename mono_delivery_time to tstamp_type for scalabilty 2024-05-23 14:14:23 -07:00
act_connmark.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_csum.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_ct.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_ctinfo.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_gact.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_gate.c net/sched: Switch to use hrtimer_setup() 2025-02-18 10:35:44 +01:00
act_ife.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
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: add loop detection 2025-10-16 16:25:10 -07:00
act_mpls.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_nat.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_pedit.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_police.c net_sched: act_police: use RCU in tcf_police_dump() 2025-07-11 16:01:17 -07:00
act_sample.c net: sched: act_sample: add action cookie to sample 2024-07-05 17:45:47 -07:00
act_simple.c net/sched: Remove redundant memset(0) call in reset_policy() 2025-08-12 17:13:29 -07:00
act_skbedit.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_skbmod.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_tunnel_key.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
act_vlan.c net_sched: add back BH safety to tcf_lock 2025-09-02 15:51:45 -07:00
bpf_qdisc.c bpf: Clean up individual BTF_ID code 2025-07-16 18:34:42 -07:00
cls_api.c net: sched: Don't use WARN_ON_ONCE() for -ENOMEM in tcf_classify(). 2025-10-29 18:00:37 -07:00
cls_basic.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_bpf.c net: sched: refine software bypass handling in tc_run 2025-01-20 09:21:27 +00:00
cls_cgroup.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_flow.c treewide, timers: Rename from_timer() to timer_container_of() 2025-06-08 09:07:37 +02:00
cls_flower.c net: fix geneve_opt length integer overflow 2025-04-03 15:47:35 -07:00
cls_fw.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_matchall.c net: sched: refine software bypass handling in tc_run 2025-01-20 09:21:27 +00:00
cls_route.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_u32.c net: sched: refine software bypass handling in tc_run 2025-01-20 09:21:27 +00:00
em_canid.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
em_cmp.c move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
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 net: dismiss sk_forward_alloc_get() 2025-02-19 19:05:28 -08:00
em_nbyte.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
em_text.c net/sched: replace strncpy with strscpy 2025-06-23 16:56:51 -07:00
em_u32.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
ematch.c net_sched: reject TCF_EM_SIMPLE case for complex ematch module 2022-12-19 09:43:18 +00:00
Kconfig sched: Add enqueue/dequeue of dualpi2 qdisc 2025-07-23 17:52:07 -07:00
Makefile sched: Add enqueue/dequeue of dualpi2 qdisc 2025-07-23 17:52:07 -07:00
sch_api.c net/sched: Use TC_RTAB_SIZE instead of magic number 2025-08-14 17:37:48 -07:00
sch_blackhole.c Revert "net: sched: Pass root lock to Qdisc_ops.enqueue" 2020-07-16 16:48:34 -07:00
sch_cake.c net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit 2025-08-20 19:27:08 -07:00
sch_cbs.c net/sched: cbs: Fix integer overflow in cbs_set_port_rate() 2024-10-15 18:25:47 -07:00
sch_choke.c net: sched: fix ordering of qlen adjustment 2024-12-04 12:54:22 +00:00
sch_codel.c net/sched: Fix backlog accounting in qdisc_dequeue_internal 2025-08-14 17:52:29 -07:00
sch_drr.c net_sched: drr: Fix double list add in class with netem as child qdisc 2025-04-28 15:55:06 -07:00
sch_dualpi2.c net/sched: sch_dualpi2: Run prob update timer in softirq to avoid deadlock 2025-08-19 17:49:01 -07:00
sch_etf.c net_sched: sch_tfs: implement lockless etf_dump() 2024-04-19 11:34:07 +01:00
sch_ets.c net/sched: ets: use old 'nbands' while purging unused classes 2025-08-13 18:11:48 -07:00
sch_fifo.c pfifo_tail_enqueue: Drop new packet when sch->limit == 0 2025-02-05 18:13:58 -08:00
sch_fq.c net/sched: Fix backlog accounting in qdisc_dequeue_internal 2025-08-14 17:52:29 -07:00
sch_fq_codel.c net/sched: Fix backlog accounting in qdisc_dequeue_internal 2025-08-14 17:52:29 -07:00
sch_fq_pie.c net/sched: Fix backlog accounting in qdisc_dequeue_internal 2025-08-14 17:52:29 -07:00
sch_frag.c net/sched: Use nested-BH locking for sch_frag_data_storage 2025-05-15 15:23:31 +02:00
sch_generic.c net: dev_queue_xmit() llist adoption 2025-10-16 16:25:10 -07:00
sch_gred.c sched: address a potential NULL pointer dereference in the GRED scheduler. 2025-03-06 16:35:14 -08:00
sch_hfsc.c net/sched: sch_qfq: Fix null-deref in agg_dequeue 2025-07-10 11:08:35 +02:00
sch_hhf.c net/sched: Fix backlog accounting in qdisc_dequeue_internal 2025-08-14 17:52:29 -07:00
sch_htb.c net/sched: Remove unnecessary WARNING condition for empty child qdisc in htb_activate 2025-08-20 19:27:08 -07:00
sch_ingress.c bpf: Fix too early release of tcx_entry 2024-07-08 14:07:31 -07:00
sch_mq.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00
sch_mqprio.c net/sched: mqprio: fix stack out-of-bounds write in tc entry parsing 2025-08-04 17:22:20 -07:00
sch_mqprio_lib.c net: sched: Fill in missing MODULE_DESCRIPTION for qdiscs 2023-11-01 21:49:09 -07:00
sch_mqprio_lib.h net/sched: mqprio: allow per-TC user input of FP adminStatus 2023-04-13 22:22:10 -07:00
sch_multiq.c net: sched: sch_multiq: fix possible OOB write in multiq_tune() 2024-06-05 10:50:19 +01:00
sch_netem.c net/sched: Restrict conditions for adding duplicating netems to qdisc tree 2025-07-11 15:50:21 -07:00
sch_pie.c net/sched: Fix backlog accounting in qdisc_dequeue_internal 2025-08-14 17:52:29 -07:00
sch_plug.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
sch_prio.c net_sched: prio: fix a race in prio_tune() 2025-06-12 08:05:49 -07:00
sch_qfq.c net/sched: sch_qfq: Avoid triggering might_sleep in atomic context in qfq_delete_class 2025-07-22 11:48:34 +02:00
sch_red.c Including fixes from bluetooth and wireless. 2025-06-12 09:50:36 -07:00
sch_sfb.c net/sched: Add drop reasons for AQM-based qdiscs 2024-12-17 13:27:29 +01:00
sch_sfq.c Including fixes from bluetooth and wireless. 2025-06-12 09:50:36 -07:00
sch_skbprio.c net_sched: skbprio: Remove overly strict queue assertions 2025-04-02 16:03:32 -07:00
sch_taprio.c net/sched: taprio: enforce minimum value for picos_per_byte 2025-08-01 15:15:28 -07:00
sch_tbf.c net_sched: tbf: fix a race in tbf_change() 2025-06-12 08:05:50 -07:00
sch_teql.c net: annotate writes on dev->mtu from ndo_change_mtu() 2024-05-07 16:19:14 -07:00