============================= WARNING: suspicious RCU usage 5.15.169-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 7 locks held by syz.2.141/4846: #0: ffff0000ddfe5010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline] #0: ffff0000ddfe5010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline] #0: ffff0000ddfe5010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x80/0x1fc net/socket.c:1336 #1: ffff0000c1034020 (sk_lock-AF_INET6/1){+.+.}-{0:0}, at: sctp_close+0xc8/0x800 net/sctp/socket.c:1490 #2: ffff800014c822e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #3: ffff800014c82340 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #4: ffff800014c82340 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #5: ffff0000d179d908 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #5: ffff0000d179d908 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3875 [inline] #5: ffff0000d179d908 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x8a0/0x2ac8 net/core/dev.c:4217 #6: ffff800014c822e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 stack backtrace: CPU: 0 PID: 4846 Comm: syz.2.141 Not tainted 5.15.169-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 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+0x200/0x4e8 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:3816 __dev_xmit_skb net/core/dev.c:3900 [inline] __dev_queue_xmit+0x1018/0x2ac8 net/core/dev.c:4217 dev_queue_xmit+0x24/0x34 net/core/dev.c:4285 neigh_hh_output include/net/neighbour.h:493 [inline] neigh_output include/net/neighbour.h:507 [inline] ip6_finish_output2+0x132c/0x1cec net/ipv6/ip6_output.c:130 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:201 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:211 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 net/ipv6/ip6_output.c:234 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ip6_xmit+0x1114/0x1afc net/ipv6/ip6_output.c:338 sctp_v6_xmit+0x86c/0x1078 net/sctp/ipv6.c:250 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_cmd_interpreter net/sctp/sm_sideeffect.c:1327 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x1078/0x4e80 net/sctp/sm_sideeffect.c:1170 sctp_primitive_ABORT+0x98/0xc8 net/sctp/primitive.c:104 sctp_close+0x2c0/0x800 net/sctp/socket.c:1523 inet_release+0x160/0x1d0 net/ipv4/af_inet.c:434 inet6_release+0x5c/0x78 net/ipv6/af_inet6.c:492 __sock_release net/socket.c:649 [inline] sock_close+0xb8/0x1fc net/socket.c:1336 __fput+0x1c4/0x800 fs/file_table.c:280 ____fput+0x20/0x30 fs/file_table.c:308 task_work_run+0x130/0x1e4 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] do_notify_resume+0x262c/0x32b8 arch/arm64/kernel/signal.c:946 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584