============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.4.1693/10199 is trying to acquire lock:
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2781 [inline]
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10836 [inline]
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __netdev_update_features+0xcbc/0x1e10 net/core/dev.c:11006
but task is already holding lock:
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2781 [inline]
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3303 [inline]
ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_ethtool+0x716/0x19c0 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#20);
lock(&dev_instance_lock_key#20);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by syz.4.1693/10199:
#0: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x1d0/0x19c0 net/ethtool/ioctl.c:3571
#1: ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2781 [inline]
#1: ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
#1: ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3303 [inline]
#1: ffff8880362bce98 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_ethtool+0x716/0x19c0 net/ethtool/ioctl.c:3572
stack backtrace:
CPU: 1 UID: 0 PID: 10199 Comm: syz.4.1693 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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+0x2540/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
netdev_lock include/linux/netdevice.h:2781 [inline]
netdev_lock_ops include/net/netdev_lock.h:42 [inline]
netdev_sync_lower_features net/core/dev.c:10836 [inline]
__netdev_update_features+0xcbc/0x1e10 net/core/dev.c:11006
netdev_change_features net/core/dev.c:11080 [inline]
netdev_compute_master_upper_features+0x8eb/0xab0 net/core/dev.c:12832
team_device_event+0x408/0x5b0 drivers/net/team/team_core.c:2934
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
netdev_features_change+0x85/0xc0 net/core/dev.c:1571
__dev_ethtool net/ethtool/ioctl.c:3539 [inline]
dev_ethtool+0x1541/0x19c0 net/ethtool/ioctl.c:3572
dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:777
sock_do_ioctl+0x22c/0x300 net/socket.c:1268
sock_ioctl+0x579/0x790 net/socket.c:1375
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcac601f749
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:00007fcac427e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcac6275fa0 RCX: 00007fcac601f749
RDX: 0000200000000000 RSI: 0000000000008946 RDI: 0000000000000004
RBP: 00007fcac60a3f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcac6276038 R14: 00007fcac6275fa0 R15: 00007ffc48be3098
------------[ cut here ]------------
rtmutex deadlock detected
WARNING: kernel/locking/rtmutex.c:1674 at rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1674, CPU#1: syz.4.1693/10199
Modules linked in:
CPU: 1 UID: 0 PID: 10199 Comm: syz.4.1693 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1674
Code: 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 41 54 53 83 ff dd 0f 85 86 00 00 00 48 89 f7 e8 a6 39 01 00 48 8d 3d 9f 4e 0a 04 <67> 48 0f b9 3a 4c 8d 3d 00 00 00 00 65 48 8b 1c 25 08 20 b3 91 4c
RSP: 0018:ffffc9001c2bf430 EFLAGS: 00010286
RAX: 0000000080000000 RBX: ffffc9001c2bf4c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8b3f5ac0 RDI: ffffffff8ede5970
RBP: ffffc9001c2bf5e0 R08: ffffffff8edb3677 R09: 1ffffffff1db66ce
R10: dffffc0000000000 R11: fffffbfff1db66cf R12: 1ffff92003857e94
R13: ffffffff8ad405b9 R14: ffff8880362bce40 R15: dffffc0000000000
FS: 00007fcac427e6c0(0000) GS:ffff888126dee000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcac60beb94 CR3: 000000003ae18000 CR4: 00000000003526f0
Call Trace:
__rt_mutex_slowlock kernel/locking/rtmutex.c:1734 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x666/0x6b0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:552
netdev_lock include/linux/netdevice.h:2781 [inline]
netdev_lock_ops include/net/netdev_lock.h:42 [inline]
netdev_sync_lower_features net/core/dev.c:10836 [inline]
__netdev_update_features+0xcbc/0x1e10 net/core/dev.c:11006
netdev_change_features net/core/dev.c:11080 [inline]
netdev_compute_master_upper_features+0x8eb/0xab0 net/core/dev.c:12832
team_device_event+0x408/0x5b0 drivers/net/team/team_core.c:2934
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
netdev_features_change+0x85/0xc0 net/core/dev.c:1571
__dev_ethtool net/ethtool/ioctl.c:3539 [inline]
dev_ethtool+0x1541/0x19c0 net/ethtool/ioctl.c:3572
dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:777
sock_do_ioctl+0x22c/0x300 net/socket.c:1268
sock_ioctl+0x579/0x790 net/socket.c:1375
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcac601f749
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:00007fcac427e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcac6275fa0 RCX: 00007fcac601f749
RDX: 0000200000000000 RSI: 0000000000008946 RDI: 0000000000000004
RBP: 00007fcac60a3f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcac6276038 R14: 00007fcac6275fa0 R15: 00007ffc48be3098
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 90 nop
3: 90 nop
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 41 57 push %r15
b: 41 56 push %r14
d: 41 55 push %r13
f: 41 54 push %r12
11: 53 push %rbx
12: 83 ff dd cmp $0xffffffdd,%edi
15: 0f 85 86 00 00 00 jne 0xa1
1b: 48 89 f7 mov %rsi,%rdi
1e: e8 a6 39 01 00 call 0x139c9
23: 48 8d 3d 9f 4e 0a 04 lea 0x40a4e9f(%rip),%rdi # 0x40a4ec9
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 4c 8d 3d 00 00 00 00 lea 0x0(%rip),%r15 # 0x36
36: 65 48 8b 1c 25 08 20 mov %gs:0xffffffff91b32008,%rbx
3d: b3 91
3f: 4c rex.WR