====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc2-syzkaller-00048-gc62f4b82d571 #0 Not tainted ------------------------------------------------------ syz.6.844/9140 is trying to acquire lock: ffffffff90254098 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff90254098 (nr_neigh_list_lock){+...}-{3:3}, at: nr_remove_neigh+0x25/0xe0 net/netrom/nr_route.c:307 but task is already holding lock: ffff888034fcc570 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888034fcc570 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] ffff888034fcc570 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0x1023/0x2370 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}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 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+0x159/0x7b0 net/netrom/nr_route.c:519 nr_device_event+0x134/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x1a7/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2212 [inline] call_netdevice_notifiers net/core/dev.c:2226 [inline] dev_close_many+0x33e/0x4c0 net/core/dev.c:1729 netif_close+0x1c2/0x2d0 net/core/dev.c:1742 dev_close+0x137/0x280 net/core/dev_api.c:219 bpq_device_event+0x36a/0x620 drivers/net/hamradio/bpqether.c:528 notifier_call_chain+0x1a7/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2212 [inline] call_netdevice_notifiers net/core/dev.c:2226 [inline] dev_close_many+0x33e/0x4c0 net/core/dev.c:1729 netif_close+0x1c2/0x2d0 net/core/dev.c:1742 dev_close+0x137/0x280 net/core/dev_api.c:219 bond_setup_by_slave+0x64/0x420 drivers/net/bonding/bond_main.c:1622 bond_enslave+0x7fb/0x38d0 drivers/net/bonding/bond_main.c:2034 bond_do_ioctl+0x7c9/0xc00 drivers/net/bonding/bond_main.c:4679 dev_siocbond net/core/dev_ioctl.c:502 [inline] dev_ifsioc+0x97c/0x1010 net/core/dev_ioctl.c:650 dev_ioctl+0x819/0x1380 net/core/dev_ioctl.c:821 sock_do_ioctl+0x233/0x490 net/socket.c:1204 sock_ioctl+0x644/0x900 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (nr_node_list_lock){+...}-{3:3}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517 nr_device_event+0x134/0x150 net/netrom/af_netrom.c:126 notifier_call_chain+0x1a7/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2212 [inline] call_netdevice_notifiers net/core/dev.c:2226 [inline] dev_close_many+0x33e/0x4c0 net/core/dev.c:1729 netif_close+0x1c2/0x2d0 net/core/dev.c:1742 dev_close+0x137/0x280 net/core/dev_api.c:219 bpq_device_event+0x36a/0x620 drivers/net/hamradio/bpqether.c:528 notifier_call_chain+0x1a7/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2212 [inline] call_netdevice_notifiers net/core/dev.c:2226 [inline] dev_close_many+0x33e/0x4c0 net/core/dev.c:1729 netif_close+0x1c2/0x2d0 net/core/dev.c:1742 dev_close+0x137/0x280 net/core/dev_api.c:219 bond_setup_by_slave+0x64/0x420 drivers/net/bonding/bond_main.c:1622 bond_enslave+0x7fb/0x38d0 drivers/net/bonding/bond_main.c:2034 bond_do_ioctl+0x7c9/0xc00 drivers/net/bonding/bond_main.c:4679 dev_siocbond net/core/dev_ioctl.c:502 [inline] dev_ifsioc+0x97c/0x1010 net/core/dev_ioctl.c:650 dev_ioctl+0x819/0x1380 net/core/dev_ioctl.c:821 sock_do_ioctl+0x233/0x490 net/socket.c:1204 sock_ioctl+0x644/0x900 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 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:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 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+0x1be9/0x2370 net/netrom/nr_route.c:249 nr_rt_ioctl+0xd60/0xff0 net/netrom/nr_route.c:651 sock_do_ioctl+0x15c/0x490 net/socket.c:1190 sock_ioctl+0x644/0x900 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 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.6.844/9140: #0: ffff888034fcc570 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #0: ffff888034fcc570 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] #0: ffff888034fcc570 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0x1023/0x2370 net/netrom/nr_route.c:214 stack backtrace: CPU: 1 UID: 0 PID: 9140 Comm: syz.6.844 Not tainted 6.15.0-rc2-syzkaller-00048-gc62f4b82d571 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211 check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 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+0x1be9/0x2370 net/netrom/nr_route.c:249 nr_rt_ioctl+0xd60/0xff0 net/netrom/nr_route.c:651 sock_do_ioctl+0x15c/0x490 net/socket.c:1190 sock_ioctl+0x644/0x900 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf3/0x160 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2c20b8e169 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:00007f2c21970038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f2c20db6160 RCX: 00007f2c20b8e169 RDX: 0000200000000280 RSI: 000000000000890b RDI: 000000000000000a RBP: 00007f2c20c10a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f2c20db6160 R15: 00007ffcec21e728