syzbot

============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.2849/12994 is trying to acquire lock:
ffff88807a9c4d00 (team->team_lock_key#4){+.+.}-{3:3}, at: team_port_change_check drivers/net/team/team.c:3021 [inline]
ffff88807a9c4d00 (team->team_lock_key#4){+.+.}-{3:3}, at: team_device_event+0x1d2/0x9e0 drivers/net/team/team.c:3047

but task is already holding lock:
ffff88807a9c4d00 (team->team_lock_key#4){+.+.}-{3:3}, at: team_del_slave+0x2e/0x1e0 drivers/net/team/team.c:2011

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

       CPU0
       ----
  lock(team->team_lock_key#4);
  lock(team->team_lock_key#4);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz.0.2849/12994:
 #0: ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681
 #1: ffff88807a9c4d00 (team->team_lock_key#4){+.+.}-{3:3}, at: team_del_slave+0x2e/0x1e0 drivers/net/team/team.c:2011

stack backtrace:
CPU: 1 PID: 12994 Comm: syz.0.2849 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 __lock_acquire+0x1236/0x7d10 kernel/locking/lockdep.c:-1
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 team_port_change_check drivers/net/team/team.c:3021 [inline]
 team_device_event+0x1d2/0x9e0 drivers/net/team/team.c:3047
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 dev_close_many+0x29f/0x400 net/core/dev.c:1663
 vlan_device_event+0x125e/0x1fa0 net/8021q/vlan.c:477
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 dev_close_many+0x29f/0x400 net/core/dev.c:1663
 dev_close+0x154/0x210 net/core/dev.c:1685
 team_port_del+0x4e1/0xc90 drivers/net/team/team.c:1370
 team_del_slave+0x39/0x1e0 drivers/net/team/team.c:2012
 do_set_master net/core/rtnetlink.c:2563 [inline]
 do_setlink+0xf17/0x3d60 net/core/rtnetlink.c:2788
 rtnl_group_changelink net/core/rtnetlink.c:3298 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3462 [inline]
 rtnl_newlink+0xf8d/0x1a50 net/core/rtnetlink.c:3574
 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5684
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499
 __sys_sendmsg net/socket.c:2528 [inline]
 __do_sys_sendmsg net/socket.c:2537 [inline]
 __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f099fceb799
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:00007f099df45028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f099ff64fa0 RCX: 00007f099fceb799
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007f099fd81c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f099ff65038 R14: 00007f099ff64fa0 R15: 00007ffe765e4b58
 </TASK>