lo: entered promiscuous mode bond0: entered promiscuous mode ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.1488/12075 is trying to acquire lock: ffffffff8ff61938 (nr_node_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] ffffffff8ff61938 (nr_node_list_lock){+...}-{3:3}, at: nr_rt_device_down+0xbe/0x860 net/netrom/nr_route.c:517 but task is already holding lock: ffffffff8ff618d8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] ffffffff8ff618d8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_device_down+0x28/0x860 net/netrom/nr_route.c:514 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (nr_neigh_list_lock){+...}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182 spin_lock_bh include/linux/spinlock.h:348 [inline] nr_remove_neigh net/netrom/nr_route.c:307 [inline] nr_dec_obs net/netrom/nr_route.c:472 [inline] nr_rt_ioctl+0x40c/0xf90 net/netrom/nr_route.c:692 sock_do_ioctl+0x101/0x320 net/socket.c:1313 sock_ioctl+0x5c6/0x7f0 net/socket.c:1434 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&nr_node->node_lock){+...}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182 spin_lock_bh include/linux/spinlock.h:348 [inline] nr_node_lock include/net/netrom.h:152 [inline] nr_dec_obs net/netrom/nr_route.c:459 [inline] nr_rt_ioctl+0x215/0xf90 net/netrom/nr_route.c:692 sock_do_ioctl+0x101/0x320 net/socket.c:1313 sock_ioctl+0x5c6/0x7f0 net/socket.c:1434 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (nr_node_list_lock){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182 spin_lock_bh include/linux/spinlock.h:348 [inline] nr_rt_device_down+0xbe/0x860 net/netrom/nr_route.c:517 nr_device_event+0x137/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] netif_close_many+0x2ae/0x420 net/core/dev.c:1805 netif_close+0x160/0x220 net/core/dev.c:1818 dev_close+0x10a/0x220 net/core/dev_api.c:221 bpq_device_event+0x377/0x6a0 drivers/net/hamradio/bpqether.c:531 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] __dev_notify_flags+0x16d/0x310 net/core/dev.c:9803 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9830 do_setlink+0xfa5/0x45a0 net/core/rtnetlink.c:3180 rtnl_group_changelink net/core/rtnetlink.c:3813 [inline] __rtnl_newlink net/core/rtnetlink.c:3981 [inline] rtnl_newlink+0x14ca/0x1bb0 net/core/rtnetlink.c:4109 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6995 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmsg net/socket.c:2784 [inline] __do_sys_sendmsg net/socket.c:2789 [inline] __se_sys_sendmsg net/socket.c:2787 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: nr_node_list_lock --> &nr_node->node_lock --> nr_neigh_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(nr_neigh_list_lock); lock(&nr_node->node_lock); lock(nr_neigh_list_lock); lock(nr_node_list_lock); *** DEADLOCK *** 2 locks held by syz.4.1488/12075: #0: ffffffff8fde4240 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8fde4240 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8fde4240 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4108 #1: ffffffff8ff618d8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] #1: ffffffff8ff618d8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_device_down+0x28/0x860 net/netrom/nr_route.c:514 stack backtrace: CPU: 1 UID: 0 PID: 12075 Comm: syz.4.1488 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182 spin_lock_bh include/linux/spinlock.h:348 [inline] nr_rt_device_down+0xbe/0x860 net/netrom/nr_route.c:517 nr_device_event+0x137/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] netif_close_many+0x2ae/0x420 net/core/dev.c:1805 netif_close+0x160/0x220 net/core/dev.c:1818 dev_close+0x10a/0x220 net/core/dev_api.c:221 bpq_device_event+0x377/0x6a0 drivers/net/hamradio/bpqether.c:531 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] __dev_notify_flags+0x16d/0x310 net/core/dev.c:9803 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9830 do_setlink+0xfa5/0x45a0 net/core/rtnetlink.c:3180 rtnl_group_changelink net/core/rtnetlink.c:3813 [inline] __rtnl_newlink net/core/rtnetlink.c:3981 [inline] rtnl_newlink+0x14ca/0x1bb0 net/core/rtnetlink.c:4109 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6995 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmsg net/socket.c:2784 [inline] __do_sys_sendmsg net/socket.c:2789 [inline] __se_sys_sendmsg net/socket.c:2787 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5b84f9cdd9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5b85ed3028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5b85215fa0 RCX: 00007f5b84f9cdd9 RDX: 0000000000040080 RSI: 0000200000000140 RDI: 0000000000000004 RBP: 00007f5b85032d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5b85216038 R14: 00007f5b85215fa0 R15: 00007ffc69afff18 dummy0: entered promiscuous mode eql: entered promiscuous mode ifb0: entered promiscuous mode ifb1: entered promiscuous mode virtio_net virtio1 eth0: entered promiscuous mode mac80211_hwsim hwsim0 wlan0: entered promiscuous mode mac80211_hwsim hwsim1 wlan1: entered promiscuous mode hwsim0: entered promiscuous mode ieee802154 phy0 wpan0: entered promiscuous mode ieee802154 phy1 wpan1: entered promiscuous mode teql0: entered promiscuous mode tunl0: entered promiscuous mode gre0: entered promiscuous mode gretap0: entered promiscuous mode erspan0: entered promiscuous mode ip_vti0: entered promiscuous mode ip6_vti0: entered promiscuous mode sit0: entered promiscuous mode ip6tnl0: entered promiscuous mode ip6gre0: entered promiscuous mode nr0: entered promiscuous mode nr1: entered promiscuous mode nr2: entered promiscuous mode nr3: entered promiscuous mode nr4: entered promiscuous mode nr5: entered promiscuous mode nr6: entered promiscuous mode nr7: entered promiscuous mode nr8: entered promiscuous mode nr9: entered promiscuous mode nr10: entered promiscuous mode nr11: entered promiscuous mode nr12: entered promiscuous mode nr13: entered promiscuous mode nr14: entered promiscuous mode nr15: entered promiscuous mode nr16: entered promiscuous mode nr17: entered promiscuous mode nr18: entered promiscuous mode nr19: entered promiscuous mode nr20: entered promiscuous mode nr21: entered promiscuous mode nr22: entered promiscuous mode nr23: entered promiscuous mode nr24: entered promiscuous mode nr25: entered promiscuous mode nr26: entered promiscuous mode nr27: entered promiscuous mode nr28: entered promiscuous mode nr29: entered promiscuous mode nr30: entered promiscuous mode nr31: entered promiscuous mode rose0: entered promiscuous mode rose1: entered promiscuous mode rose2: entered promiscuous mode rose3: entered promiscuous mode rose4: entered promiscuous mode rose5: entered promiscuous mode rose6: entered promiscuous mode rose7: entered promiscuous mode rose8: entered promiscuous mode rose9: entered promiscuous mode rose10: entered promiscuous mode rose11: entered promiscuous mode rose12: entered promiscuous mode rose13: entered promiscuous mode rose14: entered promiscuous mode rose15: entered promiscuous mode rose16: entered promiscuous mode rose17: entered promiscuous mode rose18: entered promiscuous mode rose19: entered promiscuous mode rose20: entered promiscuous mode rose21: entered promiscuous mode rose22: entered promiscuous mode rose23: entered promiscuous mode rose24: entered promiscuous mode rose25: entered promiscuous mode rose26: entered promiscuous mode rose27: entered promiscuous mode rose28: entered promiscuous mode rose29: entered promiscuous mode rose30: entered promiscuous mode rose31: entered promiscuous mode bpq0: entered promiscuous mode lapb0: entered promiscuous mode bpq1: entered promiscuous mode lapb1: entered promiscuous mode bpq2: entered promiscuous mode lapb2: entered promiscuous mode bpq3: entered promiscuous mode lapb3: entered promiscuous mode bpq4: entered promiscuous mode lapb4: entered promiscuous mode bpq5: entered promiscuous mode lapb5: entered promiscuous mode lowpan0: entered promiscuous mode veth0_macvtap: entered promiscuous mode bpq6: entered promiscuous mode lapb6: entered promiscuous mode bridge0: entered promiscuous mode ieee802154 phy2 wpan2: entered promiscuous mode netdevsim netdevsim3 eth1: entered promiscuous mode netdevsim netdevsim3 eth2: entered promiscuous mode netdevsim netdevsim3 eth3: entered promiscuous mode netdevsim netdevsim3 eth4: entered promiscuous mode mac80211_hwsim hwsim21 wlan2: entered promiscuous mode ieee802154 phy3 wpan3: entered promiscuous mode bpq7: entered promiscuous mode lapb7: entered promiscuous mode