From: syzbot <syzbot+aefe8555e94ae62b95c1@syzkaller.appspotmail.com>
To: coreteam@netfilter.org, davem@davemloft.net, edumazet@google.com,
fw@strlen.de, horms@kernel.org, kadlec@netfilter.org,
kuba@kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
pabeni@redhat.com, pablo@netfilter.org, phil@nwl.cc,
syzkaller-bugs@googlegroups.com
Subject: [syzbot] [netfilter?] possible deadlock in ip_set_nfnl_get_byindex
Date: Thu, 13 Nov 2025 01:46:23 -0800 [thread overview]
Message-ID: <6915a8ef.050a0220.3565dc.0025.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: e927c520e1ba Merge tag 'loongarch-fixes-6.18-1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110d97cd980000
kernel config: https://syzkaller.appspot.com/x/.config?x=609c87dcb0628493
dashboard link: https://syzkaller.appspot.com/bug?extid=aefe8555e94ae62b95c1
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-e927c520.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/216d03ed7180/vmlinux-e927c520.xz
kernel image: https://storage.googleapis.com/syzbot-assets/63801f21a529/bzImage-e927c520.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aefe8555e94ae62b95c1@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.9.6420/24339 is trying to acquire lock:
ffffffff9af8cbd8 (nfnl_subsys_ipset){+.+.}-{4:4}, at: ip_set_nfnl_get_byindex+0x7c/0x290 net/netfilter/ipset/ip_set_core.c:909
but task is already holding lock:
ffff888026b1e0d8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_valid_genid+0x35/0x140 net/netfilter/nf_tables_api.c:11499
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&nft_net->commit_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
nf_tables_dumpreset_set+0xcd/0x320 net/netfilter/nf_tables_api.c:6288
netlink_dump+0x539/0xd30 net/netlink/af_netlink.c:2327
__netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2442
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_getsetelem_reset+0x946/0xab0 net/netfilter/nf_tables_api.c:6604
nfnetlink_rcv_msg+0x583/0x1200 net/netfilter/nfnetlink.c:290
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2630
___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
__sys_sendmsg+0x16d/0x220 net/socket.c:2716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
__netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2406
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:2552
nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2630
___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
__sys_sendmsg+0x16d/0x220 net/socket.c:2716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (nfnl_subsys_ipset){+.+.}-{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+0x126f/0x1c90 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
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+0xea9/0x28f0 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:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2630
___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
__sys_sendmsg+0x16d/0x220 net/socket.c:2716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 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:
nfnl_subsys_ipset --> nlk_cb_mutex-NETFILTER --> &nft_net->commit_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&nft_net->commit_mutex);
lock(nlk_cb_mutex-NETFILTER);
lock(&nft_net->commit_mutex);
lock(nfnl_subsys_ipset);
*** DEADLOCK ***
1 lock held by syz.9.6420/24339:
#0: ffff888026b1e0d8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_valid_genid+0x35/0x140 net/netfilter/nf_tables_api.c:11499
stack backtrace:
CPU: 3 UID: 0 PID: 24339 Comm: syz.9.6420 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+0x275/0x350 kernel/locking/lockdep.c:2043
check_noncircular+0x14c/0x170 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+0x126f/0x1c90 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
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+0xea9/0x28f0 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:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2630
___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
__sys_sendmsg+0x16d/0x220 net/socket.c:2716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24a538f6c9
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:00007f24a6265038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f24a55e5fa0 RCX: 00007f24a538f6c9
RDX: 0000000000000800 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f24a5411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f24a55e6038 R14: 00007f24a55e5fa0 R15: 00007ffc70b4f688
</TASK>
Cannot find add_set index 0 as target
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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reply other threads:[~2025-11-13 9:46 UTC|newest]
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