syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.178-syzkaller #0 Not tainted
------------------------------------------------------
syz.7.738/6490 is trying to acquire lock:
ffff800016dea5b8 (nr_neigh_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff800016dea5b8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_remove_neigh net/netrom/nr_route.c:307 [inline]
ffff800016dea5b8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:472 [inline]
ffff800016dea5b8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_rt_ioctl+0x32c/0x18c8 net/netrom/nr_route.c:692

but task is already holding lock:
ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline]
ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:459 [inline]
ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: nr_rt_ioctl+0x1a8/0x18c8 net/netrom/nr_route.c:692

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+0x124/0x1c4 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:368 [inline]
       nr_node_lock include/net/netrom.h:151 [inline]
       nr_rt_device_down+0x130/0x710 net/netrom/nr_route.c:519
       nr_device_event+0x134/0x160 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:2018 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
       call_netdevice_notifiers net/core/dev.c:2044 [inline]
       dev_close_many+0x2fc/0x468 net/core/dev.c:1619
       dev_close+0x174/0x250 net/core/dev.c:1641
       bpq_device_event+0x314/0x814 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:2018 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
       call_netdevice_notifiers net/core/dev.c:2044 [inline]
       dev_close_many+0x2fc/0x468 net/core/dev.c:1619
       dev_close+0x174/0x250 net/core/dev.c:1641
       bond_setup_by_slave+0x70/0x314 drivers/net/bonding/bond_main.c:1471
       bond_enslave+0x628/0x3198 drivers/net/bonding/bond_main.c:1855
       bond_do_ioctl+0x264/0xd0c drivers/net/bonding/bond_main.c:4238
       dev_siocbond net/core/dev_ioctl.c:270 [inline]
       dev_ifsioc+0xc38/0xfe4 net/core/dev_ioctl.c:417
       dev_ioctl+0x4e0/0xd3c net/core/dev_ioctl.c:587
       sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154
       sock_ioctl+0x4f0/0x8ac net/socket.c:1257
       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+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 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+0x124/0x1c4 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:368 [inline]
       nr_rt_device_down+0xac/0x710 net/netrom/nr_route.c:517
       nr_device_event+0x134/0x160 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:2018 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
       call_netdevice_notifiers net/core/dev.c:2044 [inline]
       dev_close_many+0x2fc/0x468 net/core/dev.c:1619
       dev_close+0x174/0x250 net/core/dev.c:1641
       bpq_device_event+0x314/0x814 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:2018 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
       call_netdevice_notifiers net/core/dev.c:2044 [inline]
       dev_close_many+0x2fc/0x468 net/core/dev.c:1619
       dev_close+0x174/0x250 net/core/dev.c:1641
       bond_setup_by_slave+0x70/0x314 drivers/net/bonding/bond_main.c:1471
       bond_enslave+0x628/0x3198 drivers/net/bonding/bond_main.c:1855
       bond_do_ioctl+0x264/0xd0c drivers/net/bonding/bond_main.c:4238
       dev_siocbond net/core/dev_ioctl.c:270 [inline]
       dev_ifsioc+0xc38/0xfe4 net/core/dev_ioctl.c:417
       dev_ioctl+0x4e0/0xd3c net/core/dev_ioctl.c:587
       sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154
       sock_ioctl+0x4f0/0x8ac net/socket.c:1257
       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+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 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+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
       _raw_spin_lock_bh+0x124/0x1c4 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:368 [inline]
       nr_remove_neigh net/netrom/nr_route.c:307 [inline]
       nr_dec_obs net/netrom/nr_route.c:472 [inline]
       nr_rt_ioctl+0x32c/0x18c8 net/netrom/nr_route.c:692
       nr_ioctl+0x14c/0x4b0 net/netrom/af_netrom.c:1253
       sock_do_ioctl+0x134/0x2dc net/socket.c:1140
       sock_ioctl+0x4f0/0x8ac net/socket.c:1257
       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+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 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 ***

2 locks held by syz.7.738/6490:
 #0: ffff800016dea618 (nr_node_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
 #0: ffff800016dea618 (nr_node_list_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:457 [inline]
 #0: ffff800016dea618 (nr_node_list_lock){+...}-{2:2}, at: nr_rt_ioctl+0x104/0x18c8 net/netrom/nr_route.c:692
 #1: ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
 #1: ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline]
 #1: ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:459 [inline]
 #1: ffff0000c1c55470 (&nr_node->node_lock){+...}-{2:2}, at: nr_rt_ioctl+0x1a8/0x18c8 net/netrom/nr_route.c:692

stack backtrace:
CPU: 0 PID: 6490 Comm: syz.7.738 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 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+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x124/0x1c4 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:368 [inline]
 nr_remove_neigh net/netrom/nr_route.c:307 [inline]
 nr_dec_obs net/netrom/nr_route.c:472 [inline]
 nr_rt_ioctl+0x32c/0x18c8 net/netrom/nr_route.c:692
 nr_ioctl+0x14c/0x4b0 net/netrom/af_netrom.c:1253
 sock_do_ioctl+0x134/0x2dc net/socket.c:1140
 sock_ioctl+0x4f0/0x8ac net/socket.c:1257
 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+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584