netlink: 64 bytes leftover after parsing attributes in process `syz.1.2641'. ====================================================== WARNING: possible circular locking dependency detected 6.14.0-rc5-syzkaller-00149-gd2b9d97e89c7 #0 Not tainted ------------------------------------------------------ syz.1.2641/15015 is trying to acquire lock: ffffffff9002bcd8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff9002bcd8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_remove_neigh+0x25/0xe0 net/netrom/nr_route.c:307 but task is already holding lock: ffff888028b64a70 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888028b64a70 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] ffff888028b64a70 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0x1021/0x2360 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:2244 [inline] call_netdevice_notifiers net/core/dev.c:2258 [inline] dev_close_many+0x33c/0x4c0 net/core/dev.c:1748 dev_close+0x1c0/0x2c0 net/core/dev.c:1770 bpq_device_event+0x372/0x8d0 drivers/net/hamradio/bpqether.c:547 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9334 dev_ifsioc+0x7c2/0xe70 net/core/dev_ioctl.c:563 dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826 sock_do_ioctl+0x240/0x460 net/socket.c:1213 sock_ioctl+0x626/0x8e0 net/socket.c:1318 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:2244 [inline] call_netdevice_notifiers net/core/dev.c:2258 [inline] dev_close_many+0x33c/0x4c0 net/core/dev.c:1748 dev_close+0x1c0/0x2c0 net/core/dev.c:1770 bpq_device_event+0x372/0x8d0 drivers/net/hamradio/bpqether.c:547 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9334 dev_ifsioc+0x7c2/0xe70 net/core/dev_ioctl.c:563 dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826 sock_do_ioctl+0x240/0x460 net/socket.c:1213 sock_ioctl+0x626/0x8e0 net/socket.c:1318 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+0x1be2/0x2360 net/netrom/nr_route.c:249 nr_rt_ioctl+0xd5c/0xff0 net/netrom/nr_route.c:651 sock_do_ioctl+0x158/0x460 net/socket.c:1199 sock_ioctl+0x626/0x8e0 net/socket.c:1318 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.1.2641/15015: #0: ffff888028b64a70 (&nr_node->node_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #0: ffff888028b64a70 (&nr_node->node_lock){+...}-{3:3}, at: nr_node_lock include/net/netrom.h:152 [inline] #0: ffff888028b64a70 (&nr_node->node_lock){+...}-{3:3}, at: nr_add_node+0x1021/0x2360 net/netrom/nr_route.c:214 stack backtrace: CPU: 0 UID: 0 PID: 15015 Comm: syz.1.2641 Not tainted 6.14.0-rc5-syzkaller-00149-gd2b9d97e89c7 #0 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+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+0x1be2/0x2360 net/netrom/nr_route.c:249 nr_rt_ioctl+0xd5c/0xff0 net/netrom/nr_route.c:651 sock_do_ioctl+0x158/0x460 net/socket.c:1199 sock_ioctl+0x626/0x8e0 net/socket.c:1318 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: 0033:0x7f4927d8d169 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:00007f4928c71038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4927fa5fa0 RCX: 00007f4927d8d169 RDX: 0000400000000440 RSI: 000000000000890b RDI: 0000000000000004 RBP: 00007f4927e0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4927fa5fa0 R15: 00007ffccc226bd8