============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.3720/22562 is trying to acquire lock:
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2859 [inline]
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10948 [inline]
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: __netdev_update_features+0xd27/0x1ef0 net/core/dev.c:11118

but task is already holding lock:
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2859 [inline]
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3618 [inline]
ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: dev_ethtool+0x47e/0x29e0 net/ethtool/ioctl.c:3660
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#23);
  lock(&dev_instance_lock_key#23);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

locks held by syz.0.3720/22562: 2, last CPU#1:
 #0: ffffffff90254f20 (rtnl_mutex){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3617 [inline]
 #0: ffffffff90254f20 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x3a0/0x29e0 net/ethtool/ioctl.c:3660
 #1: ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2859 [inline]
 #1: ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 #1: ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3618 [inline]
 #1: ffff88807dbd0e70 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: dev_ethtool+0x47e/0x29e0 net/ethtool/ioctl.c:3660

stack backtrace:
CPU: 1 UID: 0 PID: 22562 Comm: syz.0.3720 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x27a/0x290 kernel/locking/lockdep.c:3085
 check_deadlock kernel/locking/lockdep.c:3137 [inline]
 validate_chain kernel/locking/lockdep.c:3939 [inline]
 __lock_acquire+0x25db/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
 netdev_lock include/linux/netdevice.h:2859 [inline]
 netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 netdev_sync_lower_features net/core/dev.c:10948 [inline]
 __netdev_update_features+0xd27/0x1ef0 net/core/dev.c:11118
 netdev_update_features+0x6f/0x100 net/core/dev.c:11175
 macvlan_device_event+0x62c/0x9e0 drivers/net/macvlan.c:1883
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline]
 call_netdevice_notifiers net/core/dev.c:2327 [inline]
 netdev_features_change+0x8d/0xd0 net/core/dev.c:1612
 dev_ethtool_locked net/ethtool/ioctl.c:3567 [inline]
 __dev_ethtool net/ethtool/ioctl.c:3625 [inline]
 dev_ethtool+0x1f21/0x29e0 net/ethtool/ioctl.c:3660
 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:744
 sock_do_ioctl+0x23e/0x320 net/socket.c:1339
 sock_ioctl+0x57a/0x7e0 net/socket.c:1446
 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:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f96ca59e159
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:00007f96cb3ab028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f96ca825fa0 RCX: 00007f96ca59e159
RDX: 0000200000000080 RSI: 0000000000008946 RDI: 0000000000000004
RBP: 00007f96ca63506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f96ca826038 R14: 00007f96ca825fa0 R15: 00007ffe8c6a07e8
 </TASK>