linux-kernel - [syzbot] [bluetooth?] WARNING: kobject bug in hci_disconnect_all

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Message-ID: <68887dc8.050a0220.3cc461.0012.GAE@google.com>
Date: Tue, 29 Jul 2025 00:52:40 -0700
From: syzbot <syzbot+860000a5278649faf5f6@...kaller.appspotmail.com>
To: johan.hedberg@...il.com, linux-bluetooth@...r.kernel.org, 
	linux-kernel@...r.kernel.org, luiz.dentz@...il.com, marcel@...tmann.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bluetooth?] WARNING: kobject bug in hci_disconnect_all_sync

Hello,

syzbot found the following issue on:

HEAD commit:    25fae0b93d1d Merge tag 'drm-fixes-2025-07-24' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=130a10a2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a4bcc0a11b3192be
dashboard link: https://syzkaller.appspot.com/bug?extid=860000a5278649faf5f6
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e51e91fa1800/disk-25fae0b9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/49603fd616e9/vmlinux-25fae0b9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/31b7fb718dea/bzImage-25fae0b9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+860000a5278649faf5f6@...kaller.appspotmail.com

Bluetooth: hci2: Opcode 0x0c1a failed: -4
Bluetooth: hci0: Opcode 0x0c1a failed: -4
------------[ cut here ]------------
kobject: '(null)' (ffff888034398be8): is not initialized, yet kobject_get() is being called.
WARNING: CPU: 1 PID: 18293 at lib/kobject.c:642 kobject_get+0x7d/0x120 lib/kobject.c:640
Modules linked in:
CPU: 1 UID: 0 PID: 18293 Comm: syz.1.2765 Not tainted 6.16.0-rc7-syzkaller-00034-g25fae0b93d1d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:kobject_get+0x7d/0x120 lib/kobject.c:640
Code: 90 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 e6 4c be f6 48 8b 33 48 c7 c7 40 8c b9 8c 48 89 da e8 44 2a 20 f6 90 <0f> 0b 90 90 eb 0c e8 c8 3a 5c f6 eb 46 e8 c1 3a 5c f6 4c 8d 73 38
RSP: 0018:ffffc900040473f0 EFLAGS: 00010246
RAX: d5e6b273e7d72b00 RBX: ffff888034398be8 RCX: 0000000000080000
RDX: ffffc9000f833000 RSI: 000000000001c99e RDI: 000000000001c99f
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfaa6c R12: ffff888034398000
R13: ffff888034398be8 R14: ffff888034398c24 R15: dffffc0000000000
FS:  00007f6d5d6746c0(0000) GS:ffff888125d23000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000015000 CR3: 000000007e615000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 hci_conn_get include/net/bluetooth/hci_core.h:1620 [inline]
 hci_disconnect_all_sync+0x115/0x350 net/bluetooth/hci_sync.c:5705
 hci_suspend_sync+0x3b8/0xc00 net/bluetooth/hci_sync.c:6188
 hci_suspend_dev+0x28d/0x4d0 net/bluetooth/hci_core.c:2851
 hci_suspend_notifier+0xf2/0x290 net/bluetooth/hci_core.c:2422
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 notifier_call_chain_robust kernel/notifier.c:120 [inline]
 blocking_notifier_call_chain_robust+0x85/0x100 kernel/notifier.c:345
 pm_notifier_call_chain_robust+0x2c/0x60 kernel/power/main.c:102
 snapshot_open+0x19c/0x280 kernel/power/user.c:77
 misc_open+0x2bc/0x330 drivers/char/misc.c:161
 chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414
 do_dentry_open+0xdf3/0x1970 fs/open.c:964
 vfs_open+0x3b/0x340 fs/open.c:1094
 do_open fs/namei.c:3896 [inline]
 path_openat+0x2ee5/0x3830 fs/namei.c:4055
 do_filp_open+0x1fa/0x410 fs/namei.c:4082
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6d5c78e9a9
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:00007f6d5d674038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6d5c9b6240 RCX: 00007f6d5c78e9a9
RDX: 0000000000040000 RSI: 0000200000000680 RDI: ffffffffffffff9c
RBP: 00007f6d5c810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000019 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f6d5c9b6240 R15: 00007fffd9731ce8
 </TASK>


---
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