syzbot

======================================================
WARNING: possible circular locking dependency detected
6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Not tainted
------------------------------------------------------
syz.1.2458/16385 is trying to acquire lock:
ffffffff8fe01658 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffffffff8fe01658 (nr_neigh_list_lock){+...}-{3:3}, at: nr_remove_neigh+0x25/0xe0 net/netrom/nr_route.c:307

but task is already holding lock:
ffff888144f21070 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888144f21070 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline]
ffff888144f21070 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0xfcb/0x2230 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+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __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+0x1a5/0x3f0 kernel/notifier.c:85
       call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
       call_netdevice_notifiers net/core/dev.c:2193 [inline]
       dev_close_many+0x33c/0x4c0 net/core/dev.c:1717
       dev_close+0x1c0/0x2c0 net/core/dev.c:1739
       bpq_device_event+0x372/0x8b0 drivers/net/hamradio/bpqether.c:547
       notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
       call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
       call_netdevice_notifiers net/core/dev.c:2193 [inline]
       dev_close_many+0x33c/0x4c0 net/core/dev.c:1717
       dev_close+0x1c0/0x2c0 net/core/dev.c:1739
       bond_setup_by_slave+0x66/0x390 drivers/net/bonding/bond_main.c:1631
       bond_enslave+0x7b4/0x3ac0 drivers/net/bonding/bond_main.c:2043
       bond_do_ioctl+0x749/0xb50 drivers/net/bonding/bond_main.c:4685
       dev_ifsioc+0xb73/0xe70
       dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826
       sock_do_ioctl+0x240/0x460 net/socket.c:1208
       sock_ioctl+0x626/0x8e0 net/socket.c:1313
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (nr_node_list_lock){+...}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __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+0x1a5/0x3f0 kernel/notifier.c:85
       call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
       call_netdevice_notifiers net/core/dev.c:2193 [inline]
       dev_close_many+0x33c/0x4c0 net/core/dev.c:1717
       dev_close+0x1c0/0x2c0 net/core/dev.c:1739
       bpq_device_event+0x372/0x8b0 drivers/net/hamradio/bpqether.c:547
       notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
       call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
       call_netdevice_notifiers net/core/dev.c:2193 [inline]
       dev_close_many+0x33c/0x4c0 net/core/dev.c:1717
       dev_close+0x1c0/0x2c0 net/core/dev.c:1739
       bond_setup_by_slave+0x66/0x390 drivers/net/bonding/bond_main.c:1631
       bond_enslave+0x7b4/0x3ac0 drivers/net/bonding/bond_main.c:2043
       bond_do_ioctl+0x749/0xb50 drivers/net/bonding/bond_main.c:4685
       dev_ifsioc+0xb73/0xe70
       dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826
       sock_do_ioctl+0x240/0x460 net/socket.c:1208
       sock_ioctl+0x626/0x8e0 net/socket.c:1313
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (nr_neigh_list_lock){+...}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __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+0x150b/0x2230 net/netrom/nr_route.c:249
       nr_rt_ioctl+0xd43/0xfb0 net/netrom/nr_route.c:651
       sock_do_ioctl+0x158/0x460 net/socket.c:1194
       sock_ioctl+0x626/0x8e0 net/socket.c:1313
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       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.1.2458/16385:
 #0: ffff888144f21070 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #0: ffff888144f21070 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline]
 #0: ffff888144f21070 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0xfcb/0x2230 net/netrom/nr_route.c:214

stack backtrace:
CPU: 0 UID: 0 PID: 16385 Comm: syz.1.2458 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 __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+0x150b/0x2230 net/netrom/nr_route.c:249
 nr_rt_ioctl+0xd43/0xfb0 net/netrom/nr_route.c:651
 sock_do_ioctl+0x158/0x460 net/socket.c:1194
 sock_ioctl+0x626/0x8e0 net/socket.c:1313
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a6e18cda9
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:00007f2a6bfd5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2a6e3a6080 RCX: 00007f2a6e18cda9
RDX: 0000000020000280 RSI: 000000000000890b RDI: 0000000000000006
RBP: 00007f2a6e20e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f2a6e3a6080 R15: 00007ffe6703ebe8
 </TASK>