[syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    d7e78951a8b8 Merge tag 'net-6.11-rc0' of git://git.kernel...
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=105a2f31980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8d1cf7c29e32ce12
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3c208b51873e/disk-d7e78951.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/adec146cf41c/vmlinux-d7e78951.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52f09b8f7356/bzImage-d7e78951.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff888042b68978 object type: timer_list hint: hci_cmd_timeout+0x0/0x1e0
WARNING: CPU: 0 PID: 12907 at lib/debugobjects.c:518 debug_print_object+0x17a/0x1f0 lib/debugobjects.c:515
Modules linked in:
CPU: 0 PID: 12907 Comm: syz-executor Not tainted 6.10.0-syzkaller-09703-gd7e78951a8b8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:debug_print_object+0x17a/0x1f0 lib/debugobjects.c:515
Code: e8 1b 7f 42 fd 4c 8b 0b 48 c7 c7 c0 72 20 8c 48 8b 74 24 08 48 89 ea 44 89 e1 4d 89 f8 ff 34 24 e8 db 5b 9e fc 48 83 c4 08 90 <0f> 0b 90 90 ff 05 fc 35 f8 0a 48 83 c4 10 5b 41 5c 41 5d 41 5e 41
RSP: 0018:ffffc9000e6bf838 EFLAGS: 00010282
RAX: da48afca993a8400 RBX: ffffffff8bccb720 RCX: ffff888030a8da00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffffff8c207440 R08: ffffffff815565a2 R09: fffffbfff1c39f60
R10: dffffc0000000000 R11: fffffbfff1c39f60 R12: 0000000000000000
R13: ffffffff8c207358 R14: dffffc0000000000 R15: ffff888042b68978
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0d8f907a6c CR3: 000000000e134000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __debug_check_no_obj_freed lib/debugobjects.c:990 [inline]
 debug_check_no_obj_freed+0x45b/0x580 lib/debugobjects.c:1020
 slab_free_hook mm/slub.c:2202 [inline]
 slab_free mm/slub.c:4464 [inline]
 kfree+0x10f/0x360 mm/slub.c:4585
 hci_release_dev+0x1525/0x16b0 net/bluetooth/hci_core.c:2760
 bt_host_release+0x83/0x90 net/bluetooth/hci_sysfs.c:94
 device_release+0x99/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22f/0x480 lib/kobject.c:737
 vhci_release+0x8b/0xd0 drivers/bluetooth/hci_vhci.c:667
 __fput+0x24a/0x8a0 fs/file_table.c:422
 task_work_run+0x24f/0x310 kernel/task_work.c:222
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2f/0x27f0 kernel/exit.c:877
 do_group_exit+0x207/0x2c0 kernel/exit.c:1026
 __do_sys_exit_group kernel/exit.c:1037 [inline]
 __se_sys_exit_group kernel/exit.c:1035 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1035
 x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbfd8775b59
Code: Unable to access opcode bytes at 0x7fbfd8775b2f.
RSP: 002b:00007ffda750f638 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fbfd87e4a82 RCX: 00007fbfd8775b59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007fbfd87e4a94 R08: 00007ffda750d3d7 R09: 0000000000000bb8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 0000000000000bb8 R14: 000000000003e8dd R15: 000000000003e8ae
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    0b84db5d8f25 MAINTAINERS: add Andrew Lunn as a co-maintain..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=10505727980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7cd9e7e4a8a0a15b
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16f84030580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bd00feb30432/disk-0b84db5d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e39e30a1ae6d/vmlinux-0b84db5d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/87eafcdafd48/bzImage-0b84db5d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff88806c380978 object type: timer_list hint: hci_cmd_timeout+0x0/0x1e0
WARNING: CPU: 1 PID: 11255 at lib/debugobjects.c:517 debug_print_object+0x17a/0x1f0 lib/debugobjects.c:514
Modules linked in:
CPU: 1 UID: 0 PID: 11255 Comm: syz.1.2889 Not tainted 6.12.0-rc2-syzkaller-00216-g0b84db5d8f25 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:debug_print_object+0x17a/0x1f0 lib/debugobjects.c:514
Code: e8 5b 1a 3c fd 4c 8b 0b 48 c7 c7 e0 04 61 8c 48 8b 74 24 08 48 89 ea 44 89 e1 4d 89 f8 ff 34 24 e8 db 63 93 fc 48 83 c4 08 90 <0f> 0b 90 90 ff 05 64 a7 5a 0b 48 83 c4 10 5b 41 5c 41 5d 41 5e 41
RSP: 0018:ffffc90003e17818 EFLAGS: 00010286
RAX: b20dce31d0d23300 RBX: ffffffff8c0cd900 RCX: ffff88807aa40000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffffff8c610660 R08: ffffffff8155e402 R09: fffffbfff1cf9fd8
R10: dffffc0000000000 R11: fffffbfff1cf9fd8 R12: 0000000000000000
R13: ffffffff8c610578 R14: dffffc0000000000 R15: ffff88806c380978
FS:  00007fd4093cf6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f55ce736000 CR3: 0000000074a94000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __debug_check_no_obj_freed lib/debugobjects.c:989 [inline]
 debug_check_no_obj_freed+0x45b/0x580 lib/debugobjects.c:1019
 slab_free_hook mm/slub.c:2273 [inline]
 slab_free mm/slub.c:4579 [inline]
 kfree+0x11f/0x440 mm/slub.c:4727
 hci_release_dev+0x1525/0x16b0 net/bluetooth/hci_core.c:2759
 bt_host_release+0x83/0x90 net/bluetooth/hci_sysfs.c:94
 device_release+0x99/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22f/0x480 lib/kobject.c:737
 hci_dev_put include/net/bluetooth/hci_core.h:1581 [inline]
 hci_dev_cmd+0x296/0xa50 net/bluetooth/hci_core.c:763
 sock_do_ioctl+0x158/0x460 net/socket.c:1227
 sock_ioctl+0x626/0x8e0 net/socket.c:1346
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd40857dff9
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:00007fd4093cf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd408735f80 RCX: 00007fd40857dff9
RDX: 0000000020000240 RSI: 00000000400448dd RDI: 0000000000000004
RBP: 00007fd4085f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd408735f80 R15: 00007ffd5284c118
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    499551201b5f Merge tag 'arm64-fixes' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17916f30580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c22efbd20f8da769
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1090c0c4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10a1efe8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5ee1fc255de9/disk-49955120.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/24f10c9fac9a/vmlinux-49955120.xz
kernel image: https://storage.googleapis.com/syzbot-assets/211e35102c2e/bzImage-49955120.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff888033d51248 object type: timer_list hint: hci_devcd_timeout+0x0/0x2f0 include/linux/skbuff.h:2741
WARNING: CPU: 1 PID: 5828 at lib/debugobjects.c:612 debug_print_object+0x1a2/0x2b0 lib/debugobjects.c:612
Modules linked in:
CPU: 1 UID: 0 PID: 5828 Comm: syz-executor344 Not tainted 6.13.0-rc3-syzkaller-00209-g499551201b5f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:debug_print_object+0x1a2/0x2b0 lib/debugobjects.c:612
Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 54 48 8b 14 dd a0 7f b1 8b 41 56 4c 89 e6 48 c7 c7 20 74 b1 8b e8 4f 59 bc fc 90 <0f> 0b 90 90 58 83 05 b6 5a 7f 0b 01 48 83 c4 18 5b 5d 41 5c 41 5d
RSP: 0018:ffffc90003faf768 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff815a16c9
RDX: ffff888028419e00 RSI: ffffffff815a16d6 RDI: 0000000000000001
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff8bb17ac0
R13: ffffffff8b4f8020 R14: ffffffff8a2ad340 R15: ffffc90003faf878
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f6d80ebeb8 CR3: 000000007c30e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __debug_check_no_obj_freed lib/debugobjects.c:1099 [inline]
 debug_check_no_obj_freed+0x4b7/0x600 lib/debugobjects.c:1129
 slab_free_hook mm/slub.c:2284 [inline]
 slab_free mm/slub.c:4613 [inline]
 kfree+0x2b3/0x4b0 mm/slub.c:4761
 hci_release_dev+0x4d9/0x600 net/bluetooth/hci_core.c:2758
 bt_host_release+0x6a/0xb0 net/bluetooth/hci_sysfs.c:87
 device_release+0xa1/0x240 drivers/base/core.c:2567
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1e4/0x5a0 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3773
 vhci_release+0x81/0xf0 drivers/bluetooth/hci_vhci.c:665
 __fput+0x3f8/0xb60 fs/file_table.c:450
 task_work_run+0x14e/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x2576/0x2610 kernel/signal.c:3017
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f977f68926a
Code: Unable to access opcode bytes at 0x7f977f689240.
RSP: 002b:00007ffc28c89690 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f977f68926a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f977f6e1049 R09: 00007f977f6e1049
R10: 0000000000008000 R11: 0000000000000293 R12: 00007f977f6e1049
R13: 00007ffc28c896e0 R14: 00007ffc28c89720 R15: 0000000000000000
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Forwarded: Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)
Author: abysamross@gmail.com

#syz test

Forwarded: Re: Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: Re: Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)
Author: abysamross@gmail.com

#syz test

======================================================================

From 006a3d0d3cc1b5e7be6d4eec2cbafacdbd40816c Mon Sep 17 00:00:00 2001
From: Aby Sam Ross <abysamross@gmail.com>
Date: Tue, 17 Mar 2026 00:21:32 +0530
Subject: [PATCH v1 1/1] Bluetooth: hci_release_dev: cancel coredump work

The hci device's coredump timeout work remains active when the memory
associated with the hci device is freed up in hci_release_dev(), causing
an active object to be freed.
Cancel all hci coredump related work while in hci_release_dev().

Signed-off-by: Aby Sam Ross <abysamross@gmail.com>
---
 include/net/bluetooth/coredump.h | 3 +++
 net/bluetooth/coredump.c         | 7 +++++++
 net/bluetooth/hci_core.c         | 1 +
 3 files changed, 11 insertions(+)

diff --git a/include/net/bluetooth/coredump.h b/include/net/bluetooth/coredump.h
index 72f51b587a04..18318a1f8e1a 100644
--- a/include/net/bluetooth/coredump.h
+++ b/include/net/bluetooth/coredump.h
@@ -71,6 +71,7 @@ int hci_devcd_append(struct hci_dev *hdev, struct sk_buff *skb);
 int hci_devcd_append_pattern(struct hci_dev *hdev, u8 pattern, u32 len);
 int hci_devcd_complete(struct hci_dev *hdev);
 int hci_devcd_abort(struct hci_dev *hdev);
+void hci_devcd_cancel_work_sync(struct hci_dev *hdev);
 
 #else
 
@@ -111,6 +112,8 @@ static inline int hci_devcd_abort(struct hci_dev *hdev)
 	return -EOPNOTSUPP;
 }
 
+static inline void hci_devcd_cancel_work_sync(struct hci_dev *hdev) {}
+
 #endif /* CONFIG_DEV_COREDUMP */
 
 #endif /* __COREDUMP_H */
diff --git a/net/bluetooth/coredump.c b/net/bluetooth/coredump.c
index 720cb79adf96..e3b65d627019 100644
--- a/net/bluetooth/coredump.c
+++ b/net/bluetooth/coredump.c
@@ -84,6 +84,13 @@ static void hci_devcd_notify(struct hci_dev *hdev, int state)
 		hdev->dump.notify_change(hdev, state);
 }
 
+
+void hci_devcd_cancel_work_sync(struct hci_dev *hdev)
+{
+    cancel_work_sync(&hdev->dump.dump_rx);
+    cancel_delayed_work_sync(&hdev->dump.dump_timeout);
+}
+
 /* Call with hci_dev_lock only. */
 void hci_devcd_reset(struct hci_dev *hdev)
 {
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 31308c1de4ec..95416cd0d580 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2749,6 +2749,7 @@ void hci_release_dev(struct hci_dev *hdev)
 
 	destroy_workqueue(hdev->workqueue);
 	destroy_workqueue(hdev->req_workqueue);
+    hci_devcd_cancel_work_sync(hdev);
 
 	hci_dev_lock(hdev);
 	hci_bdaddr_list_clear(&hdev->reject_list);
-- 
2.53.0

Forwarded: test syzbot+b170dbf55520ebf5969a

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: test syzbot+b170dbf55520ebf5969a
Author: abysamross@gmail.com

#syz test

Forwarded: test fix for syzbot+b170dbf55520ebf5969a

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: test fix for syzbot+b170dbf55520ebf5969a
Author: abysamross@gmail.com

#syz test

===============================
From 4c574f30487b7aa767f29689692e1e54d672c508 Mon Sep 17 00:00:00 2001
From: Aby Sam Ross <abysamross@gmail.com>
Date: Sat, 21 Mar 2026 15:12:16 +0530
Subject: [PATCH v1 1/1] Bluetooth: hci_release_dev: disable delayed hci
 devcoredump timeout work

It is not necessary that the pending delayed hci devcoredump timeout
work, hdev->dump.dump_timeout, submitted to the hdev->workqueue by the
bluetooth devcoredump state machine, hci_devcd_rx() ( -->
hci_devcd_handle_pkt_init()) will be reset by it or by the timeout func
hci_devcd_timeout() before destroying the workqueue or before the hci
device is freed up in hci_release_dev().

In this bug the active delayed devcoredump timeout work's timer object
is active when the memory associated with the hci device is freed up in
hci_release_dev() causing the ODEBUG WARNING.

Make sure that the delayed devcoredump timeout work is disabled before
the hdev->workqueue is destroyed and before the hdev memory is freed in
hci_release_dev().

Tested the change with the syzbot reproducer that uses a vhci device
locally on x86_64 and on syzbot portal as well.

Closes: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
Tested-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com
Reported-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com
Signed-off-by: Aby Sam Ross <abysamross@gmail.com>
---
 net/bluetooth/hci_core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 31308c1de4ec..3e7b4c8576b2 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2747,6 +2747,9 @@ void hci_release_dev(struct hci_dev *hdev)
 	kfree_const(hdev->hw_info);
 	kfree_const(hdev->fw_info);
 
+	if (hdev->dump.supported) {
+		disable_delayed_work_sync(&hdev->dump.dump_timeout);
+	}
 	destroy_workqueue(hdev->workqueue);
 	destroy_workqueue(hdev->req_workqueue);
 
-- 
2.53.0

Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING: ODEBUG bug in hci_release_dev

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff88807ea79460 object type: timer_list hint: hci_devcd_timeout+0x0/0x2e0 net/bluetooth/coredump.c:288
WARNING: lib/debugobjects.c:629 at debug_print_object+0x18e/0x2a0 lib/debugobjects.c:629, CPU#0: syz.4.25/6752
Modules linked in:
CPU: 0 UID: 0 PID: 6752 Comm: syz.4.25 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:debug_print_object+0x19b/0x2a0 lib/debugobjects.c:629
Code: b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 48 8d 3d 32 a5 b9 0b 41 56 48 8b 14 dd 00 c5 13 8c 4c 89 e6 <67> 48 0f b9 3a 58 83 05 2c 48 af 0b 01 48 83 c4 18 5b 5d 41 5c 41
RSP: 0018:ffffc90003877708 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffffffff8c13c440 RSI: ffffffff8c13c060 RDI: ffffffff90b567e0
RBP: 0000000000000001 R08: ffff88807ea79460 R09: ffffffff8bb07a00
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8c13c060
R13: ffffffff8bb07a40 R14: ffffffff8a8eae60 R15: ffffc90003877808
FS:  0000000000000000(0000) GS:ffff888124683000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb9c7497d9 CR3: 00000000372c4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __debug_check_no_obj_freed lib/debugobjects.c:1116 [inline]
 debug_check_no_obj_freed+0x4da/0x630 lib/debugobjects.c:1146
 __free_pages_prepare mm/page_alloc.c:1440 [inline]
 __free_frozen_pages+0x392/0x10d0 mm/page_alloc.c:2978
 hci_release_dev+0x4ef/0x630 net/bluetooth/hci_core.c:2777
 bt_host_release+0x6a/0xb0 net/bluetooth/hci_sysfs.c:87
 device_release+0xa4/0x240 drivers/base/core.c:2565
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1f7/0x640 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3797
 vhci_release+0x185/0x230 drivers/bluetooth/hci_vhci.c:691
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc71939a379
Code: Unable to access opcode bytes at 0x7fc71939a34f.
RSP: 002b:00007fc71a1760e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007fc7195e5fa8 RCX: 00007fc71939a379
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fc7195e5fac
RBP: 00007fc7195e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7195e6038 R14: 00007ffef7196040 R15: 00007ffef7196128
 </TASK>
----------------
Code disassembly (best guess):
   0:	b8 00 00 00 00       	mov    $0x0,%eax
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	lcall  (bad)
   8:	df 48 89             	fisttps -0x77(%rax)
   b:	fa                   	cli
   c:	48 c1 ea 03          	shr    $0x3,%rdx
  10:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
  14:	75 4f                	jne    0x65
  16:	48 8d 3d 32 a5 b9 0b 	lea    0xbb9a532(%rip),%rdi        # 0xbb9a54f
  1d:	41 56                	push   %r14
  1f:	48 8b 14 dd 00 c5 13 	mov    -0x73ec3b00(,%rbx,8),%rdx
  26:	8c
  27:	4c 89 e6             	mov    %r12,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	58                   	pop    %rax
  30:	83 05 2c 48 af 0b 01 	addl   $0x1,0xbaf482c(%rip)        # 0xbaf4863
  37:	48 83 c4 18          	add    $0x18,%rsp
  3b:	5b                   	pop    %rbx
  3c:	5d                   	pop    %rbp
  3d:	41 5c                	pop    %r12
  3f:	41                   	rex.B


Tested on:

commit:         f338e773 Linux 7.0-rc4
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16ce78da580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6f764aea3bbb63e1
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

Note: no patches were applied.

Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com
Tested-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com

Tested on:

commit:         2d1373e4 Merge tag 'for-7.0-rc4-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1130e2d6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6f764aea3bbb63e1
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17fea8da580000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING: ODEBUG bug in hci_release_dev

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff8880603c9460 object type: timer_list hint: hci_devcd_timeout+0x0/0x2e0 net/bluetooth/coredump.c:288
WARNING: lib/debugobjects.c:629 at debug_print_object+0x18e/0x2a0 lib/debugobjects.c:629, CPU#0: syz.2.21/6604
Modules linked in:
CPU: 0 UID: 0 PID: 6604 Comm: syz.2.21 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:debug_print_object+0x19b/0x2a0 lib/debugobjects.c:629
Code: b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 48 8d 3d 82 9b b9 0b 41 56 48 8b 14 dd 80 c8 13 8c 4c 89 e6 <67> 48 0f b9 3a 58 83 05 ac 3d af 0b 01 48 83 c4 18 5b 5d 41 5c 41
RSP: 0018:ffffc90003147708 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffffffff8c13c7c0 RSI: ffffffff8c13c3e0 RDI: ffffffff90b575b0
RBP: 0000000000000001 R08: ffff8880603c9460 R09: ffffffff8bb07a00
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8c13c3e0
R13: ffffffff8bb07a40 R14: ffffffff8a8eca20 R15: ffffc90003147808
FS:  0000000000000000(0000) GS:ffff888124680000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f871e8d1140 CR3: 000000002be6c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __debug_check_no_obj_freed lib/debugobjects.c:1116 [inline]
 debug_check_no_obj_freed+0x4da/0x630 lib/debugobjects.c:1146
 __free_pages_prepare mm/page_alloc.c:1440 [inline]
 __free_frozen_pages+0x392/0x10d0 mm/page_alloc.c:2978
 hci_release_dev+0x4ef/0x630 net/bluetooth/hci_core.c:2777
 bt_host_release+0x6a/0xb0 net/bluetooth/hci_sysfs.c:87
 device_release+0xa4/0x240 drivers/base/core.c:2565
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1f7/0x640 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3797
 vhci_release+0x185/0x230 drivers/bluetooth/hci_vhci.c:691
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcff159a379
Code: Unable to access opcode bytes at 0x7fcff159a34f.
RSP: 002b:00007fcff24b80e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007fcff17e5fa8 RCX: 00007fcff159a379
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fcff17e5fac
RBP: 00007fcff17e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcff17e6038 R14: 00007ffef3a4d530 R15: 00007ffef3a4d618
 </TASK>
----------------
Code disassembly (best guess):
   0:	b8 00 00 00 00       	mov    $0x0,%eax
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	lcall  (bad)
   8:	df 48 89             	fisttps -0x77(%rax)
   b:	fa                   	cli
   c:	48 c1 ea 03          	shr    $0x3,%rdx
  10:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
  14:	75 4f                	jne    0x65
  16:	48 8d 3d 82 9b b9 0b 	lea    0xbb99b82(%rip),%rdi        # 0xbb99b9f
  1d:	41 56                	push   %r14
  1f:	48 8b 14 dd 80 c8 13 	mov    -0x73ec3780(,%rbx,8),%rdx
  26:	8c
  27:	4c 89 e6             	mov    %r12,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	58                   	pop    %rax
  30:	83 05 ac 3d af 0b 01 	addl   $0x1,0xbaf3dac(%rip)        # 0xbaf3de3
  37:	48 83 c4 18          	add    $0x18,%rsp
  3b:	5b                   	pop    %rbx
  3c:	5d                   	pop    %rbp
  3d:	41 5c                	pop    %r12
  3f:	41                   	rex.B


Tested on:

commit:         a0c83177 Merge tag 'drm-fixes-2026-03-21' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f1d0ca580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6f764aea3bbb63e1
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

Note: no patches were applied.

Re: [syzbot] [bluetooth?] WARNING: ODEBUG bug in hci_release_dev (2)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com
Tested-by: syzbot+b170dbf55520ebf5969a@syzkaller.appspotmail.com

Tested on:

commit:         a0c83177 Merge tag 'drm-fixes-2026-03-21' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11ea66da580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6f764aea3bbb63e1
dashboard link: https://syzkaller.appspot.com/bug?extid=b170dbf55520ebf5969a
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=10b01e16580000

Note: testing is done by a robot and is best-effort only.