====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.16/6102 is trying to acquire lock: ffff8000164fcd78 (nr_neigh_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:369 [inline] ffff8000164fcd78 (nr_neigh_list_lock){+...}-{2:2}, at: nr_remove_neigh+0x30/0xec net/netrom/nr_route.c:307 but task is already holding lock: ffff0000cfb4d870 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:369 [inline] ffff0000cfb4d870 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline] ffff0000cfb4d870 (&nr_node->node_lock){+...}-{2:2}, at: nr_add_node+0xd78/0x2150 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){+...}-{2:2}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x114/0x1b4 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:369 [inline] nr_node_lock include/net/netrom.h:151 [inline] nr_rt_device_down+0x12c/0x680 net/netrom/nr_route.c:519 nr_device_event+0x138/0x164 net/netrom/af_netrom.c:126 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2062 [inline] call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] dev_close_many+0x2c8/0x438 net/core/dev.c:1663 dev_close+0x14c/0x204 net/core/dev.c:1685 bpq_device_event+0x318/0x814 drivers/net/hamradio/bpqether.c:548 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2062 [inline] call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] dev_close_many+0x2c8/0x438 net/core/dev.c:1663 dev_close+0x14c/0x204 net/core/dev.c:1685 bond_setup_by_slave+0x70/0x318 drivers/net/bonding/bond_main.c:1474 bond_enslave+0x6f8/0x3284 drivers/net/bonding/bond_main.c:1864 bond_do_ioctl+0x710/0xb68 drivers/net/bonding/bond_main.c:4254 dev_siocbond net/core/dev_ioctl.c:270 [inline] dev_ifsioc+0x9dc/0xbbc net/core/dev_ioctl.c:404 dev_ioctl+0x4b8/0xc7c net/core/dev_ioctl.c:572 sock_do_ioctl+0x198/0x258 net/socket.c:1161 sock_ioctl+0x238/0x860 net/socket.c:1266 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+0x98/0x2b0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #1 (nr_node_list_lock){+...}-{2:2}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x114/0x1b4 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:369 [inline] nr_rt_device_down+0xb4/0x680 net/netrom/nr_route.c:517 nr_device_event+0x138/0x164 net/netrom/af_netrom.c:126 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2062 [inline] call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] dev_close_many+0x2c8/0x438 net/core/dev.c:1663 dev_close+0x14c/0x204 net/core/dev.c:1685 bpq_device_event+0x318/0x814 drivers/net/hamradio/bpqether.c:548 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2062 [inline] call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] dev_close_many+0x2c8/0x438 net/core/dev.c:1663 dev_close+0x14c/0x204 net/core/dev.c:1685 bond_setup_by_slave+0x70/0x318 drivers/net/bonding/bond_main.c:1474 bond_enslave+0x6f8/0x3284 drivers/net/bonding/bond_main.c:1864 bond_do_ioctl+0x710/0xb68 drivers/net/bonding/bond_main.c:4254 dev_siocbond net/core/dev_ioctl.c:270 [inline] dev_ifsioc+0x9dc/0xbbc net/core/dev_ioctl.c:404 dev_ioctl+0x4b8/0xc7c net/core/dev_ioctl.c:572 sock_do_ioctl+0x198/0x258 net/socket.c:1161 sock_ioctl+0x238/0x860 net/socket.c:1266 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+0x98/0x2b0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 -> #0 (nr_neigh_list_lock){+...}-{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+0x2870/0x67ec kernel/locking/lockdep.c:5012 lock_acquire+0x1f4/0x618 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x114/0x1b4 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:369 [inline] nr_remove_neigh+0x30/0xec net/netrom/nr_route.c:307 nr_add_node+0x197c/0x2150 net/netrom/nr_route.c:249 nr_rt_ioctl+0xc38/0xe40 net/netrom/nr_route.c:651 nr_ioctl+0x19c/0x4ac net/netrom/af_netrom.c:1253 sock_do_ioctl+0x100/0x258 net/socket.c:1147 sock_ioctl+0x238/0x860 net/socket.c:1266 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+0x98/0x2b0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 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.0.16/6102: #0: ffff0000cfb4d870 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:369 [inline] #0: ffff0000cfb4d870 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline] #0: ffff0000cfb4d870 (&nr_node->node_lock){+...}-{2:2}, at: nr_add_node+0xd78/0x2150 net/netrom/nr_route.c:214 stack backtrace: CPU: 1 PID: 6102 Comm: syz.0.16 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: dump_backtrace+0x0/0x458 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2011 check_noncircular+0x264/0x2f8 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+0x2870/0x67ec kernel/locking/lockdep.c:5012 lock_acquire+0x1f4/0x618 kernel/locking/lockdep.c:5623 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x114/0x1b4 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:369 [inline] nr_remove_neigh+0x30/0xec net/netrom/nr_route.c:307 nr_add_node+0x197c/0x2150 net/netrom/nr_route.c:249 nr_rt_ioctl+0xc38/0xe40 net/netrom/nr_route.c:651 nr_ioctl+0x19c/0x4ac net/netrom/af_netrom.c:1253 sock_do_ioctl+0x100/0x258 net/socket.c:1147 sock_ioctl+0x238/0x860 net/socket.c:1266 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+0x98/0x2b0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 bond0: (slave rose0): Error: Device is in use and cannot be enslaved