==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first kernel/locking/mutex.c:199 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:694 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x801/0x1350 kernel/locking/mutex.c:776
Read of size 8 at addr ffff88805e8180a8 by task khidpd_15c25886/16290

CPU: 0 UID: 0 PID: 16290 Comm: khidpd_15c25886 Not tainted syzkaller #0 PREEMPT(full) 
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
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 __mutex_waiter_is_first kernel/locking/mutex.c:199 [inline]
 __mutex_lock_common kernel/locking/mutex.c:694 [inline]
 __mutex_lock+0x801/0x1350 kernel/locking/mutex.c:776
 l2cap_unregister_user+0x6a/0x1b0 net/bluetooth/l2cap_core.c:1729
 hidp_session_thread+0x3c9/0x410 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>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88805e819380 pfn:0x5e818
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001584d08 ffff8880b8840ac0 0000000000000000
raw: ffff88805e819380 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x40dc0(GFP_KERNEL|__GFP_ZERO|__GFP_COMP), pid 15763, tgid 15763 (syz-executor), ts 313449788956, free_ts 331931924691
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
 prep_new_page mm/page_alloc.c:1853 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3879
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 ___kmalloc_large_node+0x4e/0x100 mm/slub.c:5593
 __kmalloc_large_node_noprof+0x18/0x90 mm/slub.c:5624
 __do_kmalloc_node mm/slub.c:5640 [inline]
 __kmalloc_noprof+0x4bd/0x800 mm/slub.c:5664
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 hci_alloc_dev_priv+0x28/0x2060 net/bluetooth/hci_core.c:2448
 hci_alloc_dev include/net/bluetooth/hci_core.h:1761 [inline]
 __vhci_create_device drivers/bluetooth/hci_vhci.c:421 [inline]
 vhci_create_device+0x120/0x650 drivers/bluetooth/hci_vhci.c:479
 vhci_get_user drivers/bluetooth/hci_vhci.c:536 [inline]
 vhci_write+0x3ce/0x4a0 drivers/bluetooth/hci_vhci.c:616
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 15763 tgid 15763 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901
 bt_host_release+0x82/0x90 net/bluetooth/hci_sysfs.c:87
 device_release+0x9e/0x1d0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x228/0x480 lib/kobject.c:737
 vhci_release+0x15a/0x1a0 drivers/bluetooth/hci_vhci.c:691
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6c5/0x2310 kernel/exit.c:973
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1114
 __do_sys_exit_group kernel/exit.c:1125 [inline]
 __se_sys_exit_group kernel/exit.c:1123 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1123
 __pfx_syscall_get_nr+0x0/0x10 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88805e817f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805e818000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805e818080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff88805e818100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805e818180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================