syzbot |
sign-in | mailing list | source | docs |
| Title | Rank 🛈 | Repro | Cause bisect | Fix bisect | Count | Last | Reported | Patched | Status |
|---|---|---|---|---|---|---|---|---|---|
| possible deadlock in ip_set_nfnl_get_byindex netfilter | 4 | 9 | 6h58m | 53d | 0/29 | closed as dup on 2026/01/05 09:18 | |||
| possible deadlock in nf_tables_dumpreset_rules netfilter | 4 | 1 | 1d07h | 23h52m | 0/29 | closed as dup on 2026/01/05 09:15 |
| Title | Replies (including bot) | Last reply |
|---|---|---|
| [syzbot] [netfilter?] possible deadlock in nf_tables_dumpreset_obj | 6 (7) | 2025/12/23 13:14 |
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.970/9330 is trying to acquire lock:
ffff888012d4ccd8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_dumpreset_obj+0x6f/0xa0 net/netfilter/nf_tables_api.c:8491
but task is already holding lock:
ffff88802bce36f0 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}, at: __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
__netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404
netlink_dump_start include/linux/netlink.h:341 [inline]
ip_set_dump+0x17f/0x210 net/netfilter/ipset/ip_set_core.c:1717
nfnetlink_rcv_msg+0x9fc/0x1200 net/netfilter/nfnetlink.c:302
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
__sys_sendmsg+0x16d/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (nfnl_subsys_ipset){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
ip_set_nfnl_get_byindex+0x7c/0x290 net/netfilter/ipset/ip_set_core.c:909
set_target_v1_checkentry+0x1ac/0x570 net/netfilter/xt_set.c:313
xt_check_target+0x27c/0xa40 net/netfilter/x_tables.c:1038
nft_target_init+0x459/0x7d0 net/netfilter/nft_compat.c:267
nf_tables_newexpr net/netfilter/nf_tables_api.c:3527 [inline]
nf_tables_newrule+0xedd/0x2910 net/netfilter/nf_tables_api.c:4358
nfnetlink_rcv_batch+0x190d/0x2350 net/netfilter/nfnetlink.c:526
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:649 [inline]
nfnetlink_rcv+0x3c1/0x430 net/netfilter/nfnetlink.c:667
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
__sys_sendmsg+0x16d/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&nft_net->commit_mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1669/0x2890 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
nf_tables_dumpreset_obj+0x6f/0xa0 net/netfilter/nf_tables_api.c:8491
netlink_dump+0x539/0xd30 net/netlink/af_netlink.c:2325
__netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2440
netlink_dump_start include/linux/netlink.h:341 [inline]
nft_netlink_dump_start_rcu+0x81/0x1f0 net/netfilter/nf_tables_api.c:1286
nf_tables_getobj_reset+0x56b/0x6b0 net/netfilter/nf_tables_api.c:8626
nfnetlink_rcv_msg+0x583/0x1200 net/netfilter/nfnetlink.c:290
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
__sys_sendmsg+0x16d/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&nft_net->commit_mutex --> nfnl_subsys_ipset --> nlk_cb_mutex-NETFILTER
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(nlk_cb_mutex-NETFILTER);
lock(nfnl_subsys_ipset);
lock(nlk_cb_mutex-NETFILTER);
lock(&nft_net->commit_mutex);
*** DEADLOCK ***
1 lock held by syz.3.970/9330:
#0: ffff88802bce36f0 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}, at: __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404
stack backtrace:
CPU: 0 UID: 0 PID: 9330 Comm: syz.3.970 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x275/0x340 kernel/locking/lockdep.c:2043
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1669/0x2890 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
nf_tables_dumpreset_obj+0x6f/0xa0 net/netfilter/nf_tables_api.c:8491
netlink_dump+0x539/0xd30 net/netlink/af_netlink.c:2325
__netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2440
netlink_dump_start include/linux/netlink.h:341 [inline]
nft_netlink_dump_start_rcu+0x81/0x1f0 net/netfilter/nf_tables_api.c:1286
nf_tables_getobj_reset+0x56b/0x6b0 net/netfilter/nf_tables_api.c:8626
nfnetlink_rcv_msg+0x583/0x1200 net/netfilter/nfnetlink.c:290
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
__sys_sendmsg+0x16d/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb7e7b8f7c9
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:00007fb7e8a9c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb7e7de5fa0 RCX: 00007fb7e7b8f7c9
RDX: 0000000004004004 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007fb7e7c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb7e7de6038 R14: 00007fb7e7de5fa0 R15: 00007fffe518fab8
</TASK>
| Time | Kernel | Commit | Syzkaller | Config | Log | Report | Syz repro | C repro | VM info | Assets (help?) | Manager | Title |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2025/12/16 00:54 | upstream | 8f0b4cce4481 | d1b870e1 | .config | console log | report | info | [disk image (non-bootable)] [vmlinux] [kernel image] | ci-qemu-upstream | possible deadlock in nf_tables_dumpreset_obj |