linux-next test error: possible deadlock in cfg80211_netdev_notifier_call

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b28241d8 Add linux-next specific files for 20210127
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13316b44d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=37c8f99c7210a867
dashboard link: https://syzkaller.appspot.com/bug?extid=3d2d5e6cc3fb15c6a0fd
compiler: gcc (GCC) 10.1.0-syz 20200507

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d2d5e...@syzkaller.appspotmail.com

batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
device hsr_slave_0 entered promiscuous mode
device hsr_slave_1 entered promiscuous mode
============================================
WARNING: possible recursive locking detected
5.11.0-rc5-next-20210127-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.0/8425 is trying to acquire lock:
ffff8881446785e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5267 [inline]
ffff8881446785e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_netdev_notifier_call+0x615/0x1180 net/wireless/core.c:1393

but task is already holding lock:
ffff8881446785e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5267 [inline]
ffff8881446785e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: virt_wifi_newlink+0x4cb/0x940 drivers/net/wireless/virt_wifi.c:540

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

CPU0
----
lock(&rdev->wiphy.mtx);
lock(&rdev->wiphy.mtx);

*** DEADLOCK ***

May be due to missing lock nesting notation

2 locks held by syz-executor.0/8425:
#0: ffffffff8cc71b08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8cc71b08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5550
#1: ffff8881446785e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5267 [inline]
#1: ffff8881446785e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: virt_wifi_newlink+0x4cb/0x940 drivers/net/wireless/virt_wifi.c:540

stack backtrace:
CPU: 1 PID: 8425 Comm: syz-executor.0 Not tainted 5.11.0-rc5-next-20210127-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x107/0x163 lib/dump_stack.c:120
print_deadlock_bug kernel/locking/lockdep.c:2829 [inline]
check_deadlock kernel/locking/lockdep.c:2872 [inline]
validate_chain kernel/locking/lockdep.c:3661 [inline]
__lock_acquire.cold+0x14c/0x3b4 kernel/locking/lockdep.c:4899
lock_acquire kernel/locking/lockdep.c:5509 [inline]
lock_acquire+0x1a8/0x720 kernel/locking/lockdep.c:5474
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103
wiphy_lock include/net/cfg80211.h:5267 [inline]
cfg80211_netdev_notifier_call+0x615/0x1180 net/wireless/core.c:1393
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2040
call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
call_netdevice_notifiers net/core/dev.c:2066 [inline]
register_netdevice+0x1034/0x14a0 net/core/dev.c:10008
virt_wifi_newlink+0x4d3/0x940 drivers/net/wireless/virt_wifi.c:541
__rtnl_newlink+0x108b/0x16e0 net/core/rtnetlink.c:3443
rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491
rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:674
__sys_sendto+0x21c/0x320 net/socket.c:1977
__do_sys_sendto net/socket.c:1989 [inline]
__se_sys_sendto net/socket.c:1985 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:1985
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417c97
Code: 2c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 81 19 00 00 c3 48 83 ec 08 e8 e7 fa ff ff 48 89 04 24 49 89 ca b8 2c 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 2d fb ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffd43a145b0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000016b4300 RCX: 0000000000417c97
RDX: 000000000000004c RSI: 00000000016b4350 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffd43a145c0 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00000000016b4350 R15: 0000000000000003


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