INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 1 UID: 0 PID: 11553 Comm: khidpd_10000008 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:984
 register_lock_class+0xff/0x320 kernel/locking/lockdep.c:1299
 __lock_acquire+0xae/0x2cf0 kernel/locking/lockdep.c:5112
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
 set_task_blocked_on+0x27/0x150 include/linux/sched.h:2165
 __mutex_lock_common kernel/locking/mutex.c:701 [inline]
 __mutex_lock+0x811/0x1350 kernel/locking/mutex.c:776
 l2cap_unregister_user+0x6a/0x1b0 net/bluetooth/l2cap_core.c:1729
 hidp_session_thread+0x3a1/0x420 net/bluetooth/hidp/core.c:1304
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
 non-slab/vmalloc memory
list_del corruption. prev->next should be ffffc900041efb20, but was 0000000000000000. (prev=ffff8880a24e80a8)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 11553 Comm: khidpd_10000008 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 4b 3e 6d fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c 27 8f fd 49 8b 17 48 c7 c7 20 88 c0 8b 48 89 de 4c 89 f9 e8 b7 c2 8e fc 90 <0f> 0b 4c 89 f7 e8 1c 3e 6d fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0018:ffffc900041ef9f0 EFLAGS: 00010046
RAX: 000000000000006d RBX: ffffc900041efb20 RCX: 39c452441902b500
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc900041efbd0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bbae2c R12: 1ffff1101449d015
R13: dffffc0000000000 R14: ffff8880a24e80a8 R15: ffff8880a24e80a8
FS:  0000000000000000(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f56b6bb5000 CR3: 000000005c761000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:132 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del include/linux/list.h:237 [inline]
 __mutex_remove_waiter kernel/locking/mutex.c:221 [inline]
 __mutex_lock_common kernel/locking/mutex.c:742 [inline]
 __mutex_lock+0xbe3/0x1350 kernel/locking/mutex.c:776
 l2cap_unregister_user+0x6a/0x1b0 net/bluetooth/l2cap_core.c:1729
 hidp_session_thread+0x3a1/0x420 net/bluetooth/hidp/core.c:1304
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x15a/0x190 lib/list_debug.c:62
Code: e8 4b 3e 6d fd 43 80 3c 2c 00 74 08 4c 89 ff e8 4c 27 8f fd 49 8b 17 48 c7 c7 20 88 c0 8b 48 89 de 4c 89 f9 e8 b7 c2 8e fc 90 <0f> 0b 4c 89 f7 e8 1c 3e 6d fd 43 80 3c 2c 00 74 08 4c 89 ff e8 1d
RSP: 0018:ffffc900041ef9f0 EFLAGS: 00010046
RAX: 000000000000006d RBX: ffffc900041efb20 RCX: 39c452441902b500
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc900041efbd0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bbae2c R12: 1ffff1101449d015
R13: dffffc0000000000 R14: ffff8880a24e80a8 R15: ffff8880a24e80a8
FS:  0000000000000000(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f56b6bb5000 CR3: 000000005c761000 CR4: 0000000000350ef0