============================================
WARNING: possible recursive locking detected
5.5.0-rc5-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.1/8794 is trying to acquire lock:
ffffffff8adc4fb0 (&table[i].mutex){+.+.}, at: nfnl_lock+0x24/0x30 net/netfilter/nfnetlink.c:62

but task is already holding lock:
ffffffff8adc4fb0 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline]
ffffffff8adc4fb0 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x80d/0xcd0 net/netfilter/nfnetlink.c:224

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&table[i].mutex);
  lock(&table[i].mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz-executor.1/8794:
 #0: ffffffff8adc4fb0 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline]
 #0: ffffffff8adc4fb0 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x80d/0xcd0 net/netfilter/nfnetlink.c:224
 #1: ffff8880a734d5d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0x75/0x1170 net/netlink/af_netlink.c:2199

stack backtrace:
CPU: 1 PID: 8794 Comm: syz-executor.1 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 print_deadlock_bug kernel/locking/lockdep.c:2371 [inline]
 check_deadlock kernel/locking/lockdep.c:2412 [inline]
 validate_chain+0x61c1/0x7be0 kernel/locking/lockdep.c:2955
 __lock_acquire+0xc5a/0x1bc0 kernel/locking/lockdep.c:3955
 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4485
 __mutex_lock_common+0x16e/0x2f30 kernel/locking/mutex.c:956
 __mutex_lock kernel/locking/mutex.c:1103 [inline]
 mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118
 nfnl_lock+0x24/0x30 net/netfilter/nfnetlink.c:62
 dump_init net/netfilter/ipset/ip_set_core.c:1506 [inline]
 ip_set_dump_start+0x7b9/0x1830 net/netfilter/ipset/ip_set_core.c:1543
 netlink_dump+0x4ed/0x1170 net/netlink/af_netlink.c:2244
 __netlink_dump_start+0x5cb/0x7b0 net/netlink/af_netlink.c:2352
 netlink_dump_start include/linux/netlink.h:233 [inline]
 ip_set_dump+0x107/0x160 net/netfilter/ipset/ip_set_core.c:1692
 nfnetlink_rcv_msg+0x9ae/0xcd0 net/netfilter/nfnetlink.c:229
 netlink_rcv_skb+0x19e/0x3e0 net/netlink/af_netlink.c:2477
 nfnetlink_rcv+0x1e0/0x1e50 net/netfilter/nfnetlink.c:563
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0xa2c/0xd50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2330
 ___sys_sendmsg net/socket.c:2384 [inline]
 __sys_sendmsg+0x1ed/0x290 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2424
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45aff9
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f387a737c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f387a7386d4 RCX: 000000000045aff9
RDX: 0000000020000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008cf R14: 00000000004c9eb1 R15: 000000000075bfd4