[v6.1] WARNING: ODEBUG bug in free_unref_page_prepare

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0182cb5b74ee Linux 6.1.162
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1088ea52580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=c721706ff6f373642089
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91a9c745b7a1/disk-0182cb5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a26ca15eb2ec/vmlinux-0182cb5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/767cda5049bb/bzImage-0182cb5b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c72170...@syzkaller.appspotmail.com

Bluetooth: hci0: Opcode 0x0c1a failed: -22
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: hci_dev_do_close net/bluetooth/hci_core.c:-1 [inline]
ODEBUG: free active (active state 0) object type: timer_list hint: hci_cmd_timeout+0x0/0x1e0 net/bluetooth/hci_core.c:1006
WARNING: CPU: 1 PID: 14346 at lib/debugobjects.c:518 debug_print_object lib/debugobjects.c:515 [inline]
WARNING: CPU: 1 PID: 14346 at lib/debugobjects.c:518 __debug_check_no_obj_freed lib/debugobjects.c:979 [inline]
WARNING: CPU: 1 PID: 14346 at lib/debugobjects.c:518 debug_check_no_obj_freed+0x43c/0x530 lib/debugobjects.c:1009
Modules linked in:
CPU: 1 PID: 14346 Comm: syz.4.3207 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:debug_print_object lib/debugobjects.c:515 [inline]
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:979 [inline]
RIP: 0010:debug_check_no_obj_freed+0x43c/0x530 lib/debugobjects.c:1009
Code: ef e8 b8 f1 bd fd 4c 8b 45 00 48 c7 c7 80 16 df 8a 48 c7 c6 40 13 df 8a 48 c7 c2 e0 17 df 8a 8b 0c 24 4d 89 e9 e8 f4 75 38 fd <0f> 0b 4c 8b 6c 24 18 48 b9 00 00 00 00 00 fc ff df ff 05 65 92 0a
RSP: 0018:ffffc90003c879f0 EFLAGS: 00010246
RAX: 459f91c6e2623300 RBX: ffffffff96e11790 RCX: 0000000000080000
RDX: ffffc9000e161000 RSI: 000000000000595e RDI: 000000000000595f
RBP: ffffffff8a8def40 R08: ffffc90003c87667 R09: 1ffff92000790ecc
R10: dffffc0000000000 R11: fffff52000790ecd R12: ffff88805f028000
R13: ffffffff89330f20 R14: ffff88805f024000 R15: ffff88805f024c08
FS: 00007f3ad5a516c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31a18ff8 CR3: 0000000030fca000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
free_pages_prepare mm/page_alloc.c:1492 [inline]
free_pcp_prepare mm/page_alloc.c:1536 [inline]
free_unref_page_prepare+0x2a6/0x9a0 mm/page_alloc.c:3413
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508
free_large_kmalloc+0xfd/0x190 mm/slab_common.c:913
bt_host_release+0x7e/0x90 net/bluetooth/hci_sysfs.c:85
device_release+0x92/0x1c0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:681 [inline]
kobject_release lib/kobject.c:712 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x21d/0x460 lib/kobject.c:729
hci_dev_put include/net/bluetooth/hci_core.h:1456 [inline]
hci_dev_cmd+0x1ed/0x760 net/bluetooth/hci_core.c:795
sock_do_ioctl+0xfb/0x320 net/socket.c:1201
sock_ioctl+0x4d2/0x710 net/socket.c:1320
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3ad4b9af79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3ad5a51028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3ad4e15fa0 RCX: 00007f3ad4b9af79
RDX: 00002000000003c0 RSI: 00000000400448dd RDI: 0000000000000006
RBP: 00007f3ad4c316e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3ad4e16038 R14: 00007f3ad4e15fa0 R15: 00007ffeef54ea68
</TASK>


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