============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.1.1057/9741 is trying to acquire lock: ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2785 [inline] ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10881 [inline] ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __netdev_update_features+0xcdc/0x1de0 net/core/dev.c:11051 but task is already holding lock: ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2785 [inline] ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3303 [inline] ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: dev_ethtool+0x754/0x1ae0 net/ethtool/ioctl.c:3572 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.1.1057/9741: #0: ffffffff8fbd0b48 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x1e1/0x1ae0 net/ethtool/ioctl.c:3571 #1: ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2785 [inline] #1: ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] #1: ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3303 [inline] #1: ffff888055cc8d88 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: dev_ethtool+0x754/0x1ae0 net/ethtool/ioctl.c:3572 stack backtrace: CPU: 1 UID: 0 PID: 9741 Comm: syz.1.1057 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: 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:10881 [inline] __netdev_update_features+0xcdc/0x1de0 net/core/dev.c:11051 netdev_change_features net/core/dev.c:11125 [inline] netdev_compute_master_upper_features+0x8eb/0xac0 net/core/dev.c:12880 team_device_event+0x40d/0x5b0 drivers/net/team/team_core.c:3010 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] netdev_features_change+0x8d/0xd0 net/core/dev.c:1590 __dev_ethtool net/ethtool/ioctl.c:3539 [inline] dev_ethtool+0x162c/0x1ae0 net/ethtool/ioctl.c:3572 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:749 compat_ifr_data_ioctl net/socket.c:3413 [inline] compat_sock_ioctl_trans net/socket.c:3443 [inline] compat_sock_ioctl+0xc4d/0xcb0 net/socket.c:3533 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x5ea/0x950 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x20d/0x640 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf703ef6c Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8 RSP: 002b:00000000f540c50c EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 000000000000000d RCX: 0000000000008946 RDX: 0000000080000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 90 nop 1: 85 d2 test %edx,%edx 3: 74 0a je 0xf 5: 89 ce mov %ecx,%esi 7: 81 e6 ff 0f 00 00 and $0xfff,%esi d: 89 32 mov %esi,(%rdx) f: 85 c0 test %eax,%eax 11: 74 05 je 0x18 13: c1 e9 0c shr $0xc,%ecx 16: 89 08 mov %ecx,(%rax) 18: 31 c0 xor %eax,%eax 1a: 5e pop %rsi 1b: 5d pop %rbp 1c: c3 ret 1d: 90 nop 1e: 0f 1f 00 nopl (%rax) 21: 51 push %rcx 22: 52 push %rdx 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 90 nop 33: 90 nop 34: 90 nop 35: 90 nop 36: 90 nop 37: 90 nop 38: 90 nop 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 58 pop %rax 3f: b8 .byte 0xb8