====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.7626/32699 is trying to acquire lock: ffffffff8f4744b8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff8f4744b8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_remove_neigh+0x25/0xe0 net/netrom/nr_route.c:307 but task is already holding lock: ffff888030b9ef70 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888030b9ef70 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] ffff888030b9ef70 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0xcce/0x2570 net/netrom/nr_route.c:214 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&nr_node->node_lock){+...}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_node_lock include/net/netrom.h:152 [inline] nr_rt_device_down+0x12a/0x720 net/netrom/nr_route.c:519 nr_device_event+0x137/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] netif_close_many+0x29c/0x410 net/core/dev.c:1798 netif_close+0x158/0x210 net/core/dev.c:1811 dev_close+0x10a/0x220 net/core/dev_api.c:220 bpq_device_event+0x377/0x6a0 drivers/net/hamradio/bpqether.c:528 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] netif_close_many+0x29c/0x410 net/core/dev.c:1798 netif_close+0x158/0x210 net/core/dev.c:1811 dev_close+0x10a/0x220 net/core/dev_api.c:220 bond_setup_by_slave+0x5f/0x3d0 drivers/net/bonding/bond_main.c:1476 bond_enslave+0x6ca/0x3ac0 drivers/net/bonding/bond_main.c:1881 bond_do_ioctl+0x68d/0x870 drivers/net/bonding/bond_main.c:4525 bond_siocdevprivate+0x18f/0x1f0 drivers/net/bonding/bond_main.c:-1 dev_siocdevprivate net/core/dev_ioctl.c:539 [inline] dev_ifsioc+0xb57/0xf00 net/core/dev_ioctl.c:651 dev_ioctl+0x84c/0x1150 net/core/dev_ioctl.c:869 sock_ioctl+0x719/0x790 net/socket.c:1300 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+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (nr_node_list_lock){+...}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_rt_device_down+0xa9/0x720 net/netrom/nr_route.c:517 nr_device_event+0x137/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] netif_close_many+0x29c/0x410 net/core/dev.c:1798 netif_close+0x158/0x210 net/core/dev.c:1811 dev_close+0x10a/0x220 net/core/dev_api.c:220 bpq_device_event+0x377/0x6a0 drivers/net/hamradio/bpqether.c:528 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] netif_close_many+0x29c/0x410 net/core/dev.c:1798 netif_close+0x158/0x210 net/core/dev.c:1811 dev_close+0x10a/0x220 net/core/dev_api.c:220 bond_setup_by_slave+0x5f/0x3d0 drivers/net/bonding/bond_main.c:1476 bond_enslave+0x6ca/0x3ac0 drivers/net/bonding/bond_main.c:1881 bond_do_ioctl+0x68d/0x870 drivers/net/bonding/bond_main.c:4525 bond_siocdevprivate+0x18f/0x1f0 drivers/net/bonding/bond_main.c:-1 dev_siocdevprivate net/core/dev_ioctl.c:539 [inline] dev_ifsioc+0xb57/0xf00 net/core/dev_ioctl.c:651 dev_ioctl+0x84c/0x1150 net/core/dev_ioctl.c:869 sock_ioctl+0x719/0x790 net/socket.c:1300 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+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (nr_neigh_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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_remove_neigh+0x25/0xe0 net/netrom/nr_route.c:307 nr_add_node+0x1d9f/0x2570 net/netrom/nr_route.c:249 nr_rt_ioctl+0xc12/0xd50 net/netrom/nr_route.c:651 sock_do_ioctl+0xdc/0x300 net/socket.c:1254 sock_ioctl+0x576/0x790 net/socket.c:1375 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+0xec/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_neigh_list_lock --> nr_node_list_lock --> &nr_node->node_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&nr_node->node_lock); lock(nr_node_list_lock); lock(&nr_node->node_lock); lock(nr_neigh_list_lock); *** DEADLOCK *** 1 lock held by syz.0.7626/32699: #0: ffff888030b9ef70 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #0: ffff888030b9ef70 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] #0: ffff888030b9ef70 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0xcce/0x2570 net/netrom/nr_route.c:214 stack backtrace: CPU: 1 UID: 0 PID: 32699 Comm: syz.0.7626 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_remove_neigh+0x25/0xe0 net/netrom/nr_route.c:307 nr_add_node+0x1d9f/0x2570 net/netrom/nr_route.c:249 nr_rt_ioctl+0xc12/0xd50 net/netrom/nr_route.c:651 sock_do_ioctl+0xdc/0x300 net/socket.c:1254 sock_ioctl+0x576/0x790 net/socket.c:1375 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+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc597d8f749 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:00007fc598cd9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc597fe5fa0 RCX: 00007fc597d8f749 RDX: 0000200000000000 RSI: 000000000000890b RDI: 0000000000000004 RBP: 00007fc597e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc597fe6038 R14: 00007fc597fe5fa0 R15: 00007ffcc8937e18