============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.1.15729/11399 is trying to acquire lock:
ffff88811e950d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __netdev_update_features+0xcb1/0x1be0

but task is already holding lock:
ffff88811e950d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_ethtool+0x716/0x19b0
and the lock comparison function returns 0:

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

       CPU0
       ----
  lock(&dev_instance_lock_key#20);
  lock(&dev_instance_lock_key#20);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz.1.15729/11399:
 #0: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x1d0/0x19b0
 #1: ffff88811e950d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_ethtool+0x716/0x19b0

stack backtrace:
CPU: 1 UID: 0 PID: 11399 Comm: syz.1.15729 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_deadlock_bug+0x28b/0x2a0
 validate_chain+0x1a3f/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 __mutex_lock+0x187/0x1350
 __netdev_update_features+0xcb1/0x1be0
 netdev_change_features+0x72/0xd0
 bond_compute_features+0x615/0x680
 bond_netdev_event+0x72e/0xe80
 notifier_call_chain+0x1b6/0x3e0
 netdev_features_change+0x85/0xc0
 dev_ethtool+0x1536/0x19b0
 dev_ioctl+0x392/0x1150
 sock_do_ioctl+0x22c/0x300
 sock_ioctl+0x576/0x790
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdf29b8ebe9
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:00007fdf2a9f1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdf29dc5fa0 RCX: 00007fdf29b8ebe9
RDX: 0000200000000040 RSI: 0000000000008946 RDI: 000000000000000c
RBP: 00007fdf29c11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdf29dc6038 R14: 00007fdf29dc5fa0 R15: 00007fffba266858
 </TASK>
