==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first kernel/locking/mutex.c:197 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common+0xb10/0x1f60 kernel/locking/mutex.c:681
Read of size 8 at addr ffff0000d7fbc060 by task khidpd_0c450101/4456

CPU: 1 PID: 4456 Comm: khidpd_0c450101 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
 __mutex_waiter_is_first kernel/locking/mutex.c:197 [inline]
 __mutex_lock_common+0xb10/0x1f60 kernel/locking/mutex.c:681
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 l2cap_unregister_user+0x70/0x18c net/bluetooth/l2cap_core.c:1895
 hidp_session_thread+0x3e8/0x478 net/bluetooth/hidp/core.c:1305
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

The buggy address belongs to the physical page:
page:00000000a24e4a6d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117fbc
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d7fbbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000d7fbbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000d7fbc000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                       ^
 ffff0000d7fbc080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000d7fbc100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
================================================================================
UBSAN: array-index-out-of-bounds in kernel/locking/qspinlock.c:131:9
index 546 is out of range for type 'unsigned long[8]'
CPU: 1 PID: 4456 Comm: khidpd_0c450101 Tainted: G    B              syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 ubsan_epilogue+0x14/0x48 lib/ubsan.c:151
 __ubsan_handle_out_of_bounds+0xd0/0xf8 lib/ubsan.c:282
 decode_tail kernel/locking/qspinlock.c:131 [inline]
 queued_spin_lock_slowpath+0x8a8/0xc18 kernel/locking/qspinlock.c:471
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x2f4/0x2f8 kernel/locking/spinlock_debug.c:115
 __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
 _raw_spin_lock+0x5c/0x6c kernel/locking/spinlock.c:154
 __mutex_lock_common+0x974/0x1f60 kernel/locking/mutex.c:699
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 l2cap_unregister_user+0x70/0x18c net/bluetooth/l2cap_core.c:1895
 hidp_session_thread+0x3e8/0x478 net/bluetooth/hidp/core.c:1305
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
================================================================================