====================================================== WARNING: possible circular locking dependency detected 5.15.146-syzkaller #0 Not tainted ------------------------------------------------------ ksoftirqd/0/14 is trying to acquire lock: ffff00010b137218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff00010b137218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3869 [inline] ffff00010b137218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1994/0x2a6c net/core/dev.c:4213 but task is already holding lock: ffff0000d56a2c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000d56a2c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff0000d56a2c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (_xmit_ETHER#2){+.-.}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __netif_tx_lock include/linux/netdevice.h:4429 [inline] sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3844 [inline] __dev_queue_xmit+0x14b4/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 lapbeth_data_transmit+0x1dc/0x294 drivers/net/wan/lapbether.c:259 lapb_data_transmit+0x8c/0xb0 net/lapb/lapb_iface.c:447 lapb_transmit_buffer+0x178/0x204 net/lapb/lapb_out.c:149 lapb_send_control+0x220/0x320 net/lapb/lapb_subr.c:251 lapb_establish_data_link+0x94/0xec lapb_device_event+0x348/0x4f4 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 __dev_notify_flags+0x2ac/0x534 dev_change_flags+0xc8/0x154 net/core/dev.c:8886 devinet_ioctl+0x858/0x17fc net/ipv4/devinet.c:1142 inet_ioctl+0x2ac/0x500 net/ipv4/af_inet.c:975 sock_do_ioctl+0x134/0x2dc net/socket.c:1138 sock_ioctl+0x4f0/0x8ac net/socket.c:1255 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #0 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __dev_xmit_skb net/core/dev.c:3869 [inline] __dev_queue_xmit+0x1994/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_resolve_output+0x52c/0x5dc net/core/neighbour.c:1497 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbf8/0x1788 net/ipv6/ndisc.c:509 ndisc_send_ns+0x538/0x6ec net/ipv6/ndisc.c:651 ndisc_solicit+0x2f4/0x47c neigh_probe+0xc4/0x138 net/core/neighbour.c:1010 __neigh_event_send+0xca4/0x1338 net/core/neighbour.c:1171 neigh_event_send include/net/neighbour.h:438 [inline] neigh_resolve_output+0x178/0x5dc net/core/neighbour.c:1481 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161 ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1943 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:1963 icmpv6_push_pending_frames+0x244/0x398 net/ipv6/icmp.c:311 icmp6_send+0x11a4/0x1b18 net/ipv6/icmp.c:630 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x44/0x4a8 net/ipv6/route.c:2790 dst_link_failure+0x11c/0x160 include/net/dst.h:422 ip_tunnel_xmit+0x16e0/0x2358 net/ipv4/ip_tunnel.c:816 __gre_xmit net/ipv4/ip_gre.c:469 [inline] erspan_xmit+0x9cc/0x14cc net/ipv4/ip_gre.c:718 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3633 sch_direct_xmit+0x2e0/0x484 net/sched/sch_generic.c:342 qdisc_restart net/sched/sch_generic.c:407 [inline] __qdisc_run+0x878/0x1fc0 net/sched/sch_generic.c:415 __dev_xmit_skb net/core/dev.c:3902 [inline] __dev_queue_xmit+0x1068/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 br_dev_queue_push_xmit+0x56c/0x70c net/bridge/br_forward.c:53 NF_HOOK+0x358/0x404 include/linux/netfilter.h:302 br_forward_finish+0x7c/0x90 net/bridge/br_forward.c:66 NF_HOOK+0x358/0x404 include/linux/netfilter.h:302 __br_forward+0x2f0/0x458 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xc8/0x188 net/bridge/br_forward.c:189 br_flood+0x28c/0x41c net/bridge/br_forward.c:231 br_dev_xmit+0xd8c/0x1280 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3633 __dev_queue_xmit+0x13a8/0x2a6c net/core/dev.c:4248 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_resolve_output+0x52c/0x5dc net/core/neighbour.c:1497 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbf8/0x1788 net/ipv6/ndisc.c:509 ndisc_send_rs+0x494/0x5fc net/ipv6/ndisc.c:703 addrconf_rs_timer+0x308/0x5a8 net/ipv6/addrconf.c:3942 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1737 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1750 __do_softirq+0x344/0xdb0 kernel/softirq.c:558 run_ksoftirqd+0x68/0x258 kernel/softirq.c:921 smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164 kthread+0x37c/0x45c kernel/kthread.c:319 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(_xmit_ETHER#2); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); lock(_xmit_ETHER#2); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** 14 locks held by ksoftirqd/0/14: #0: ffff800018977a00 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline] #0: ffff800018977a00 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd0/0x8f0 kernel/time/timer.c:1411 #1: ffff800014af15e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:268 #2: ffff800014af1640 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:268 #3: ffff800014af1640 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:268 #4: ffff800014af15e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:268 #5: ffff800014af1640 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:268 #6: ffff00010b137148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: __dev_xmit_skb net/core/dev.c:3897 [inline] #6: ffff00010b137148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: __dev_queue_xmit+0x1054/0x2a6c net/core/dev.c:4213 #7: ffff0000d56a2c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #7: ffff0000d56a2c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] #7: ffff0000d56a2c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 #8: ffff0000d2803360 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #8: ffff0000d2803360 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0x100/0x188 net/ipv6/icmp.c:118 #9: ffff800014af15e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:268 #10: ffff800014af1640 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:268 #11: ffff800014af15e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:268 #12: ffff800014af1640 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:268 #13: ffff800014af1640 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:268 stack backtrace: CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.146-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 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 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __dev_xmit_skb net/core/dev.c:3869 [inline] __dev_queue_xmit+0x1994/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_resolve_output+0x52c/0x5dc net/core/neighbour.c:1497 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbf8/0x1788 net/ipv6/ndisc.c:509 ndisc_send_ns+0x538/0x6ec net/ipv6/ndisc.c:651 ndisc_solicit+0x2f4/0x47c neigh_probe+0xc4/0x138 net/core/neighbour.c:1010 __neigh_event_send+0xca4/0x1338 net/core/neighbour.c:1171 neigh_event_send include/net/neighbour.h:438 [inline] neigh_resolve_output+0x178/0x5dc net/core/neighbour.c:1481 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161 ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1943 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:1963 icmpv6_push_pending_frames+0x244/0x398 net/ipv6/icmp.c:311 icmp6_send+0x11a4/0x1b18 net/ipv6/icmp.c:630 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x44/0x4a8 net/ipv6/route.c:2790 dst_link_failure+0x11c/0x160 include/net/dst.h:422 ip_tunnel_xmit+0x16e0/0x2358 net/ipv4/ip_tunnel.c:816 __gre_xmit net/ipv4/ip_gre.c:469 [inline] erspan_xmit+0x9cc/0x14cc net/ipv4/ip_gre.c:718 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3633 sch_direct_xmit+0x2e0/0x484 net/sched/sch_generic.c:342 qdisc_restart net/sched/sch_generic.c:407 [inline] __qdisc_run+0x878/0x1fc0 net/sched/sch_generic.c:415 __dev_xmit_skb net/core/dev.c:3902 [inline] __dev_queue_xmit+0x1068/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 br_dev_queue_push_xmit+0x56c/0x70c net/bridge/br_forward.c:53 NF_HOOK+0x358/0x404 include/linux/netfilter.h:302 br_forward_finish+0x7c/0x90 net/bridge/br_forward.c:66 NF_HOOK+0x358/0x404 include/linux/netfilter.h:302 __br_forward+0x2f0/0x458 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xc8/0x188 net/bridge/br_forward.c:189 br_flood+0x28c/0x41c net/bridge/br_forward.c:231 br_dev_xmit+0xd8c/0x1280 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3633 __dev_queue_xmit+0x13a8/0x2a6c net/core/dev.c:4248 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_resolve_output+0x52c/0x5dc net/core/neighbour.c:1497 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbf8/0x1788 net/ipv6/ndisc.c:509 ndisc_send_rs+0x494/0x5fc net/ipv6/ndisc.c:703 addrconf_rs_timer+0x308/0x5a8 net/ipv6/addrconf.c:3942 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1737 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1750 __do_softirq+0x344/0xdb0 kernel/softirq.c:558 run_ksoftirqd+0x68/0x258 kernel/softirq.c:921 smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164 kthread+0x37c/0x45c kernel/kthread.c:319 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 vkms_vblank_simulate: vblank timer overrun