======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.6.6535/22637 is trying to acquire lock:
ffff88807802f698 (nlk_cb_mutex-NETFILTER){+.+.}-{3:3}, at: __netlink_dump_start+0x11e/0x6f0 net/netlink/af_netlink.c:2310

but task is already holding lock:
ffffffff9703a1b8 (nfnl_subsys_ipset){+.+.}-{3:3}, at: nfnl_lock net/netfilter/nfnetlink.c:98 [inline]
ffffffff9703a1b8 (nfnl_subsys_ipset){+.+.}-{3:3}, at: nfnetlink_rcv_msg+0xa58/0x1290 net/netfilter/nfnetlink.c:295

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (nfnl_subsys_ipset){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
       ip_set_nfnl_get_byindex+0x63/0x230 net/netfilter/ipset/ip_set_core.c:911
       set_target_v1_checkentry+0x88/0x4f0 net/netfilter/xt_set.c:313
       xt_check_target+0x49d/0xbf0 net/netfilter/x_tables.c:1061
       nft_target_init+0x678/0x9c0 net/netfilter/nft_compat.c:268
       nf_tables_newexpr net/netfilter/nf_tables_api.c:3071 [inline]
       nf_tables_newrule+0x170a/0x2810 net/netfilter/nf_tables_api.c:3804
       nfnetlink_rcv_batch net/netfilter/nfnetlink.c:519 [inline]
       nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:639 [inline]
       nfnetlink_rcv+0x1119/0x2470 net/netfilter/nfnetlink.c:657
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
       ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
       __sys_sendmsg net/socket.c:2602 [inline]
       __do_sys_sendmsg net/socket.c:2611 [inline]
       __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&nft_net->commit_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
       nf_tables_dumpreset_obj+0x6e/0x90 net/netfilter/nf_tables_api.c:7592
       netlink_dump+0x683/0xcd0 net/netlink/af_netlink.c:2241
       __netlink_dump_start+0x52c/0x6f0 net/netlink/af_netlink.c:2343
       netlink_dump_start include/linux/netlink.h:269 [inline]
       nft_netlink_dump_start_rcu+0xdb/0x1a0 net/netfilter/nf_tables_api.c:1095
       nf_tables_getobj_reset+0x1cb/0x610 net/netfilter/nf_tables_api.c:7727
       nfnetlink_rcv_msg+0x898/0x1290 net/netfilter/nfnetlink.c:290
       netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516
       nfnetlink_rcv+0x2b0/0x2470 net/netfilter/nfnetlink.c:659
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
       ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
       __sys_sendmsg net/socket.c:2602 [inline]
       __do_sys_sendmsg net/socket.c:2611 [inline]
       __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (nlk_cb_mutex-NETFILTER){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3830 [inline]
       __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
       lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
       __netlink_dump_start+0x11e/0x6f0 net/netlink/af_netlink.c:2310
       netlink_dump_start include/linux/netlink.h:269 [inline]
       ip_set_dump+0x152/0x1e0 net/netfilter/ipset/ip_set_core.c:1719
       nfnetlink_rcv_msg+0xcab/0x1290 net/netfilter/nfnetlink.c:302
       netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516
       nfnetlink_rcv+0x2b0/0x2470 net/netfilter/nfnetlink.c:659
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
       ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
       __sys_sendmsg net/socket.c:2602 [inline]
       __do_sys_sendmsg net/socket.c:2611 [inline]
       __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  nlk_cb_mutex-NETFILTER --> &nft_net->commit_mutex --> nfnl_subsys_ipset

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(nfnl_subsys_ipset);
                               lock(&nft_net->commit_mutex);
                               lock(nfnl_subsys_ipset);
  lock(nlk_cb_mutex-NETFILTER);

 *** DEADLOCK ***

1 lock held by syz.6.6535/22637:
 #0: ffffffff9703a1b8 (nfnl_subsys_ipset){+.+.}-{3:3}, at: nfnl_lock net/netfilter/nfnetlink.c:98 [inline]
 #0: ffffffff9703a1b8 (nfnl_subsys_ipset){+.+.}-{3:3}, at: nfnetlink_rcv_msg+0xa58/0x1290 net/netfilter/nfnetlink.c:295

stack backtrace:
CPU: 1 PID: 22637 Comm: syz.6.6535 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3830 [inline]
 __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
 __netlink_dump_start+0x11e/0x6f0 net/netlink/af_netlink.c:2310
 netlink_dump_start include/linux/netlink.h:269 [inline]
 ip_set_dump+0x152/0x1e0 net/netfilter/ipset/ip_set_core.c:1719
 nfnetlink_rcv_msg+0xcab/0x1290 net/netfilter/nfnetlink.c:302
 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516
 nfnetlink_rcv+0x2b0/0x2470 net/netfilter/nfnetlink.c:659
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
 __sys_sendmsg net/socket.c:2602 [inline]
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f545679de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5457612028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5456a26090 RCX: 00007f545679de99
RDX: 0000000000000080 RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007f5456833eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5456a26128 R14: 00007f5456a26090 R15: 00007ffd2c466028
 </TASK>