syzbot

============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.8.9029/31141 is trying to acquire lock:
ffff88802f3c8d00 (team->team_lock_key#9){+.+.}-{3:3}, at: team_port_change_check drivers/net/team/team.c:3007 [inline]
ffff88802f3c8d00 (team->team_lock_key#9){+.+.}-{3:3}, at: team_device_event+0x18a/0xa20 drivers/net/team/team.c:3033

but task is already holding lock:
ffff88802f3c8d00 (team->team_lock_key#9){+.+.}-{3:3}, at: team_del_slave+0x32/0x1c0 drivers/net/team/team.c:1997

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

       CPU0
       ----
  lock(team->team_lock_key#9);
  lock(team->team_lock_key#9);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz.8.9029/31141:
 #0: ffffffff8dfbbc48 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 #0: ffffffff8dfbbc48 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6469
 #1: ffff88802f3c8d00 (team->team_lock_key#9){+.+.}-{3:3}, at: team_del_slave+0x32/0x1c0 drivers/net/team/team.c:1997

stack backtrace:
CPU: 1 PID: 31141 Comm: syz.8.9029 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain kernel/locking/lockdep.c:3856 [inline]
 __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
 team_port_change_check drivers/net/team/team.c:3007 [inline]
 team_device_event+0x18a/0xa20 drivers/net/team/team.c:3033
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 dev_close_many+0x297/0x400 net/core/dev.c:1619
 vlan_device_event+0x1806/0x1ef0 net/8021q/vlan.c:474
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 dev_close_many+0x297/0x400 net/core/dev.c:1619
 dev_close+0x150/0x200 net/core/dev.c:1641
 team_port_del+0x4c8/0xc50 drivers/net/team/team.c:1366
 team_del_slave+0x3d/0x1c0 drivers/net/team/team.c:1998
 do_set_master net/core/rtnetlink.c:2692 [inline]
 do_setlink+0xe92/0x3fb0 net/core/rtnetlink.c:2912
 rtnl_group_changelink net/core/rtnetlink.c:3454 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3713 [inline]
 rtnl_newlink+0x10af/0x2020 net/core/rtnetlink.c:3750
 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6472
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9743b8efc9
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:00007f97449eb038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9743de5fa0 RCX: 00007f9743b8efc9
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007f9743c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9743de6038 R14: 00007f9743de5fa0 R15: 00007fffdd0b4b28
 </TASK>