============================= WARNING: suspicious RCU usage 5.15.173-syzkaller #0 Not tainted ----------------------------- net/sched/sch_api.c:304 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 9 locks held by kworker/0:9/4170: #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283 #1: ffff8000207d7c00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285 #2: ffff800008007ba0 ((&peer->hb_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline] #2: ffff800008007ba0 ((&peer->hb_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd0/0x8f0 kernel/time/timer.c:1441 #3: ffff0000d397a4a0 (slock-AF_INET6){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #3: ffff0000d397a4a0 (slock-AF_INET6){+.-.}-{2:2}, at: sctp_generate_heartbeat_event+0x90/0x3dc net/sctp/sm_sideeffect.c:371 #4: ffff800014d322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #5: ffff800014d32340 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #6: ffff800014d32340 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #7: ffff0000d6a73908 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #7: ffff0000d6a73908 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3879 [inline] #7: ffff0000d6a73908 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x8a0/0x2ac8 net/core/dev.c:4221 #8: ffff800014d322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 stack backtrace: CPU: 0 PID: 4170 Comm: kworker/0:9 Not tainted 5.15.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events pwq_unbound_release_workfn Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x188/0x1e0 kernel/locking/lockdep.c:6571 qdisc_lookup+0xc8/0x64c net/sched/sch_api.c:304 qdisc_tree_reduce_backlog+0x208/0x4a4 net/sched/sch_api.c:800 pfifo_tail_enqueue+0x280/0x38c net/sched/sch_fifo.c:51 qdisc_enqueue include/net/sch_generic.h:832 [inline] tbf_enqueue+0x2f8/0x5f0 net/sched/sch_tbf.c:237 dev_qdisc_enqueue+0x60/0x35c net/core/dev.c:3820 __dev_xmit_skb net/core/dev.c:3904 [inline] __dev_queue_xmit+0x1018/0x2ac8 net/core/dev.c:4221 dev_queue_xmit+0x24/0x34 net/core/dev.c:4289 neigh_hh_output include/net/neighbour.h:493 [inline] neigh_output include/net/neighbour.h:507 [inline] ip_finish_output2+0xd3c/0x131c net/ipv4/ip_output.c:228 __ip_finish_output+0x1b0/0x458 ip_finish_output+0x40/0x218 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0x330/0x49c net/ipv4/ip_output.c:430 dst_output include/net/dst.h:443 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] __ip_queue_xmit+0xe90/0x1a04 net/ipv4/ip_output.c:532 sctp_v4_xmit+0x430/0xb00 net/sctp/protocol.c:1071 sctp_packet_transmit+0x1ec0/0x237c net/sctp/output.c:652 sctp_outq_flush_transports net/sctp/outqueue.c:1170 [inline] sctp_outq_flush+0xf74/0x2e84 net/sctp/outqueue.c:1218 sctp_outq_uncork+0x84/0xc0 net/sctp/outqueue.c:761 sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x485c/0x4e80 net/sctp/sm_sideeffect.c:1170 sctp_generate_heartbeat_event+0x2b4/0x3dc net/sctp/sm_sideeffect.c:391 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x384/0xdbc kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] invoke_softirq kernel/softirq.c:439 [inline] __irq_exit_rcu+0x268/0x4d8 kernel/softirq.c:641 irq_exit+0x14/0x88 kernel/softirq.c:665 handle_domain_irq+0xf4/0x178 kernel/irq/irqdesc.c:711 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x74/0x94 arch/arm64/kernel/entry-common.c:267 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] lockdep_unregister_key+0x338/0x3e0 kernel/locking/lockdep.c:6329 wq_unregister_lockdep kernel/workqueue.c:3518 [inline] pwq_unbound_release_workfn+0x204/0x258 kernel/workqueue.c:3756 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310 worker_thread+0x910/0x1034 kernel/workqueue.c:2457 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870