============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.2398/13321 is trying to acquire lock:
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2785 [inline]
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10882 [inline]
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __netdev_update_features+0xd16/0x1e10 net/core/dev.c:11052

but task is already holding lock:
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2785 [inline]
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3304 [inline]
ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: dev_ethtool+0x754/0x1ae0 net/ethtool/ioctl.c:3573
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#24);
  lock(&dev_instance_lock_key#24);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by syz.0.2398/13321:
 #0: ffffffff8fbc7fc8 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x1e1/0x1ae0 net/ethtool/ioctl.c:3572
 #1: ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2785 [inline]
 #1: ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 #1: ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3304 [inline]
 #1: ffff888079344d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: dev_ethtool+0x754/0x1ae0 net/ethtool/ioctl.c:3573

stack backtrace:
CPU: 0 UID: 0 PID: 13321 Comm: syz.0.2398 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x253f/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
 __mutex_lock_common kernel/locking/mutex.c:614 [inline]
 __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776
 netdev_lock include/linux/netdevice.h:2785 [inline]
 netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 netdev_sync_lower_features net/core/dev.c:10882 [inline]
 __netdev_update_features+0xd16/0x1e10 net/core/dev.c:11052
 netdev_change_features net/core/dev.c:11126 [inline]
 netdev_compute_master_upper_features+0x8eb/0xac0 net/core/dev.c:12881
 bond_slave_netdev_event drivers/net/bonding/bond_main.c:4029 [inline]
 bond_netdev_event+0x71f/0xfa0 drivers/net/bonding/bond_main.c:4074
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
 call_netdevice_notifiers net/core/dev.c:2302 [inline]
 netdev_features_change+0x8d/0xd0 net/core/dev.c:1590
 __dev_ethtool net/ethtool/ioctl.c:3540 [inline]
 dev_ethtool+0x162c/0x1ae0 net/ethtool/ioctl.c:3573
 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:749
 sock_do_ioctl+0x23e/0x320 net/socket.c:1261
 sock_ioctl+0x5c6/0x7f0 net/socket.c:1368
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f221579c799
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:00007f2216618028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2215a15fa0 RCX: 00007f221579c799
RDX: 0000200000000000 RSI: 0000000000008946 RDI: 0000000000000004
RBP: 00007f2215832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2215a16038 R14: 00007f2215a15fa0 R15: 00007ffc1bd5ed18
 </TASK>