[v5.15] possible deadlock in nr_remove_neigh

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4735586da88e Linux 5.15.176
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14981824580000
kernel config: https://syzkaller.appspot.com/x/.config?x=caf0c22a63c5c861
dashboard link: https://syzkaller.appspot.com/bug?extid=a3b4fb520bc52e171081
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e7a2d136136/disk-4735586d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7597375cf469/vmlinux-4735586d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/132474c9ad82/Image-4735586d.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a3b4fb...@syzkaller.appspotmail.com

binder: 4896:4897 got reply transaction with no transaction stack
binder: 4896:4897 transaction failed 29201/-71, size 0-24 line 2822
======================================================
WARNING: possible circular locking dependency detected
5.15.176-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.232/4897 is trying to acquire lock:
ffff800016dd88f8 (nr_neigh_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff800016dd88f8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_remove_neigh+0x30/0xec net/netrom/nr_route.c:307

but task is already holding lock:
ffff0000d5f5a470 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff0000d5f5a470 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline]
ffff0000d5f5a470 (&nr_node->node_lock){+...}-{2:2}, at: nr_add_node+0xe1c/0x1fc4 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+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+0x30/0xec net/netrom/nr_route.c:307
nr_add_node+0x17e4/0x1fc4 net/netrom/nr_route.c:249
nr_rt_ioctl+0xe58/0x18c8 net/netrom/nr_route.c:651
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 ***

1 lock held by syz.2.232/4897:
#0: ffff0000d5f5a470 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
#0: ffff0000d5f5a470 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline]
#0: ffff0000d5f5a470 (&nr_node->node_lock){+...}-{2:2}, at: nr_add_node+0xe1c/0x1fc4 net/netrom/nr_route.c:214

stack backtrace:
CPU: 0 PID: 4897 Comm: syz.2.232 Not tainted 5.15.176-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+0x30/0xec net/netrom/nr_route.c:307
nr_add_node+0x17e4/0x1fc4 net/netrom/nr_route.c:249
nr_rt_ioctl+0xe58/0x18c8 net/netrom/nr_route.c:651
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


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 4735586da88e Linux 5.15.176
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=12b67424580000

kernel config: https://syzkaller.appspot.com/x/.config?x=caf0c22a63c5c861
dashboard link: https://syzkaller.appspot.com/bug?extid=a3b4fb520bc52e171081
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12fa3618580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12e95964580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e7a2d136136/disk-4735586d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7597375cf469/vmlinux-4735586d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/132474c9ad82/Image-4735586d.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a3b4fb...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.15.176-syzkaller #0 Not tainted
------------------------------------------------------

syz-executor349/4117 is trying to acquire lock:

ffff800016dd88f8 (nr_neigh_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff800016dd88f8 (nr_neigh_list_lock){+...}-{2:2}, at: nr_remove_neigh+0x30/0xec net/netrom/nr_route.c:307

but task is already holding lock:

ffff0000d1f7dc70 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff0000d1f7dc70 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline]
ffff0000d1f7dc70 (&nr_node->node_lock){+...}-{2:2}, at: nr_add_node+0xe1c/0x1fc4 net/netrom/nr_route.c:214

1 lock held by syz-executor349/4117:
#0: ffff0000d1f7dc70 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
#0: ffff0000d1f7dc70 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:151 [inline]
#0: ffff0000d1f7dc70 (&nr_node->node_lock){+...}-{2:2}, at: nr_add_node+0xe1c/0x1fc4 net/netrom/nr_route.c:214

stack backtrace:
CPU: 0 PID: 4117 Comm: syz-executor349 Not tainted 5.15.176-syzkaller #0

bond0: (slave rose0): Error: Device is in use and cannot be enslaved


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.