============================================
WARNING: possible recursive locking detected
5.6.0-rc3-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.2/8425 is trying to acquire lock:
ffff888091340c10 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1541 [inline]
ffff888091340c10 (sk_lock-AF_INET6){+.+.}, at: inet_csk_accept+0x562/0xb00 net/ipv4/inet_connection_sock.c:492

but task is already holding lock:
ffff888091341610 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1541 [inline]
ffff888091341610 (sk_lock-AF_INET6){+.+.}, at: inet_csk_accept+0x78/0xb00 net/ipv4/inet_connection_sock.c:445

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

       CPU0
       ----
  lock(sk_lock-AF_INET6);
  lock(sk_lock-AF_INET6);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by syz-executor.2/8425:
 #0: ffff888091341610 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1541 [inline]
 #0: ffff888091341610 (sk_lock-AF_INET6){+.+.}, at: inet_csk_accept+0x78/0xb00 net/ipv4/inet_connection_sock.c:445

stack backtrace:
CPU: 1 PID: 8425 Comm: syz-executor.2 Not tainted 5.6.0-rc3-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+0x128/0x182 lib/dump_stack.c:118
 print_deadlock_bug kernel/locking/lockdep.c:2370 [inline]
 check_deadlock kernel/locking/lockdep.c:2411 [inline]
 validate_chain kernel/locking/lockdep.c:2954 [inline]
 __lock_acquire.cold.65+0x126/0x2e4 kernel/locking/lockdep.c:3954
 lock_acquire+0x19b/0x420 kernel/locking/lockdep.c:4484
 lock_sock_nested+0xaf/0xf0 net/core/sock.c:2947
 lock_sock include/net/sock.h:1541 [inline]
 inet_csk_accept+0x562/0xb00 net/ipv4/inet_connection_sock.c:492
 inet_accept+0xdd/0x6d0 net/ipv4/af_inet.c:734
 __sys_accept4_file+0x33e/0x510 net/socket.c:1758
 __sys_accept4+0x3b/0x70 net/socket.c:1809
 __do_sys_accept4 net/socket.c:1821 [inline]
 __se_sys_accept4 net/socket.c:1818 [inline]
 __x64_sys_accept4+0x8e/0xf0 net/socket.c:1818
 do_syscall_64+0xc6/0x5e0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c4a9
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:00007fc75f3e0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: ffffffffffffffda RBX: 00007fc75f3e16d4 RCX: 000000000045c4a9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000000b R14: 00000000004c2734 R15: 000000000076bf2c