====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.2543/15535 is trying to acquire lock: ffffffff8e51e058 (nr_node_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff8e51e058 (nr_node_list_lock){+...}-{2:2}, at: nr_rt_device_down+0xa9/0x720 net/netrom/nr_route.c:517 but task is already holding lock: ffffffff8e51dff8 (nr_neigh_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff8e51dff8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_rt_device_down+0x28/0x720 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){+...}-{2:2}: __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 net/netrom/nr_route.c:307 [inline] nr_dec_obs net/netrom/nr_route.c:472 [inline] nr_rt_ioctl+0x3e2/0xde0 net/netrom/nr_route.c:692 sock_do_ioctl+0xfc/0x310 net/socket.c:1219 sock_ioctl+0x5ba/0x7e0 net/socket.c:1340 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&nr_node->node_lock){+...}-{2:2}: __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_dec_obs net/netrom/nr_route.c:459 [inline] nr_rt_ioctl+0x1e5/0xde0 net/netrom/nr_route.c:692 sock_do_ioctl+0xfc/0x310 net/socket.c:1219 sock_ioctl+0x5ba/0x7e0 net/socket.c:1340 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (nr_node_list_lock){+...}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __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+0x197/0x380 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline] call_netdevice_notifiers net/core/dev.c:2091 [inline] dev_close_many+0x2a9/0x410 net/core/dev.c:1632 dev_close+0x158/0x210 net/core/dev.c:1654 bpq_device_event+0x2f4/0x8b0 drivers/net/hamradio/bpqether.c:547 notifier_call_chain+0x197/0x380 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline] call_netdevice_notifiers net/core/dev.c:2091 [inline] dev_close_many+0x2a9/0x410 net/core/dev.c:1632 dev_close+0x158/0x210 net/core/dev.c:1654 bond_setup_by_slave+0x5f/0x3f0 drivers/net/bonding/bond_main.c:1552 bond_enslave+0x8ed/0x3bd0 drivers/net/bonding/bond_main.c:1970 bond_do_ioctl+0x65b/0x9b0 drivers/net/bonding/bond_main.c:4624 dev_ioctl+0x7b4/0x1140 net/core/dev_ioctl.c:770 sock_do_ioctl+0x239/0x310 net/socket.c:1233 sock_ioctl+0x5ba/0x7e0 net/socket.c:1340 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 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.2.2543/15535: #0: ffffffff8e3c0d48 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x7a4/0x1140 net/core/dev_ioctl.c:769 #1: ffffffff8e51dff8 (nr_neigh_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffffffff8e51dff8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_rt_device_down+0x28/0x720 net/netrom/nr_route.c:514 stack backtrace: CPU: 0 PID: 15535 Comm: syz.2.2543 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __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+0x197/0x380 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline] call_netdevice_notifiers net/core/dev.c:2091 [inline] dev_close_many+0x2a9/0x410 net/core/dev.c:1632 dev_close+0x158/0x210 net/core/dev.c:1654 bpq_device_event+0x2f4/0x8b0 drivers/net/hamradio/bpqether.c:547 notifier_call_chain+0x197/0x380 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline] call_netdevice_notifiers net/core/dev.c:2091 [inline] dev_close_many+0x2a9/0x410 net/core/dev.c:1632 dev_close+0x158/0x210 net/core/dev.c:1654 bond_setup_by_slave+0x5f/0x3f0 drivers/net/bonding/bond_main.c:1552 bond_enslave+0x8ed/0x3bd0 drivers/net/bonding/bond_main.c:1970 bond_do_ioctl+0x65b/0x9b0 drivers/net/bonding/bond_main.c:4624 dev_ioctl+0x7b4/0x1140 net/core/dev_ioctl.c:770 sock_do_ioctl+0x239/0x310 net/socket.c:1233 sock_ioctl+0x5ba/0x7e0 net/socket.c:1340 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe1aad9c799 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:00007fe1abbe1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe1ab015fa0 RCX: 00007fe1aad9c799 RDX: 0000200000000180 RSI: 0000000000008990 RDI: 0000000000000008 RBP: 00007fe1aae32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe1ab016038 R14: 00007fe1ab015fa0 R15: 00007ffd35800c48 8021q: adding VLAN 0 to HW filter on device bond0 bond0: (slave rose0): Enslaving as an active interface with an up link