============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G             L     
--------------------------------------------
syz.2.557/7709 is trying to acquire lock:
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2864 [inline]
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10980 [inline]
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: __netdev_update_features+0x988/0x1894 net/core/dev.c:11150

but task is already holding lock:
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2864 [inline]
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3627 [inline]
ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: dev_ethtool+0x384/0x1a98 net/ethtool/ioctl.c:3669
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.2.557/7709: 2, last CPU#0:
 #0: ffff80008aa8eac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
 #1: ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2864 [inline]
 #1: ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 #1: ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3627 [inline]
 #1: ffff0000ee280e78 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: dev_ethtool+0x384/0x1a98 net/ethtool/ioctl.c:3669

stack backtrace:
CPU: 0 UID: 0 PID: 7709 Comm: syz.2.557 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_deadlock_bug+0x2e8/0x2f0 kernel/locking/lockdep.c:3085
 check_deadlock kernel/locking/lockdep.c:3137 [inline]
 validate_chain kernel/locking/lockdep.c:3939 [inline]
 __lock_acquire+0x2404/0x2b08 kernel/locking/lockdep.c:5288
 lock_acquire+0x13c/0x320 kernel/locking/lockdep.c:5942
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x164/0x1078 kernel/locking/mutex.c:821
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874
 netdev_lock include/linux/netdevice.h:2864 [inline]
 netdev_lock_ops include/net/netdev_lock.h:42 [inline]
 netdev_sync_lower_features net/core/dev.c:10980 [inline]
 __netdev_update_features+0x988/0x1894 net/core/dev.c:11150
 netdev_update_features+0x78/0xf4 net/core/dev.c:11207
 macvlan_device_event+0x530/0x778 drivers/net/macvlan.c:1883
 notifier_call_chain+0x1a4/0x4cc kernel/notifier.c:85
 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xb8/0x120 net/core/dev.c:2275
 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline]
 call_netdevice_notifiers net/core/dev.c:2327 [inline]
 netdev_features_change+0x84/0xcc net/core/dev.c:1612
 dev_ethtool_locked net/ethtool/ioctl.c:3576 [inline]
 __dev_ethtool net/ethtool/ioctl.c:3634 [inline]
 dev_ethtool+0x165c/0x1a98 net/ethtool/ioctl.c:3669
 dev_ioctl+0x284/0xc88 net/core/dev_ioctl.c:745
 sock_do_ioctl+0x198/0x254 net/socket.c:1339
 sock_ioctl+0x55c/0x7ec net/socket.c:1446
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606