[syzbot] [kernel?] INFO: trying to register non-static key in waveform_detach

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4c06e63b9203 Merge tag 'for-6.16-rc4-tag' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16528f70580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b29b1a0d7330d4a8
dashboard link: https://syzkaller.appspot.com/bug?extid=eec47f88bae8951c6afd
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14a66c8c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11528f70580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-4c06e63b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ff61efc838cb/vmlinux-4c06e63b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dea44d0d14bb/bzImage-4c06e63b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eec47f...@syzkaller.appspotmail.com

RBP: 00007ffc832acc70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fa16e5b5fa0 R14: 00007fa16e5b5fa0 R15: 0000000000000003
</TASK>
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 0 UID: 0 PID: 5518 Comm: syz.0.16 Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:987
register_lock_class+0x105/0x320 kernel/locking/lockdep.c:1302
__lock_acquire+0x99/0xd20 kernel/locking/lockdep.c:5115
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__timer_delete_sync+0x11f/0x2d0 kernel/time/timer.c:1602
waveform_detach+0x45/0x60 drivers/comedi/drivers/comedi_test.c:796
comedi_device_detach+0x137/0x720 drivers/comedi/drivers.c:207
comedi_device_attach+0x568/0x670 drivers/comedi/drivers.c:1000
do_devconfig_ioctl drivers/comedi/comedi_fops.c:855 [inline]
comedi_unlocked_ioctl+0x686/0xf40 drivers/comedi/comedi_fops.c:2136
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/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: 0033:0x7fa16e38e929
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:00007ffc832acc18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa16e5b5fa0 RCX: 00007fa16e38e929
RDX: 0000200000000140 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007ffc832acc70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fa16e5b5fa0 R14: 00007fa16e5b5fa0 R15: 0000000000000003
</TASK>
------------[ cut here ]------------
ODEBUG: assert_init not available (active state 0) object: ffff888059fb4800 object type: timer_list hint: 0x0
WARNING: CPU: 0 PID: 5518 at lib/debugobjects.c:615 debug_print_object+0x16b/0x1e0 lib/debugobjects.c:612
Modules linked in:
CPU: 0 UID: 0 PID: 5518 Comm: syz.0.16 Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:debug_print_object+0x16b/0x1e0 lib/debugobjects.c:612
Code: 4c 89 ff e8 27 c2 5b fd 4d 8b 0f 48 c7 c7 60 99 e2 8b 48 8b 34 24 4c 89 ea 89 e9 4d 89 f0 41 54 e8 ca e7 bb fc 48 83 c4 08 90 <0f> 0b 90 90 ff 05 c7 ef d9 0a 48 83 c4 08 5b 41 5c 41 5d 41 5e 41
RSP: 0018:ffffc90002d9f858 EFLAGS: 00010282
RAX: 475940cc4ed76c00 RBX: dffffc0000000000 RCX: ffff8880003f4880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 0000000000000000 R08: ffff88801fc24293 R09: 1ffff11003f84852
R10: dffffc0000000000 R11: ffffed1003f84853 R12: 0000000000000000
R13: ffffffff8be29b20 R14: ffff888059fb4800 R15: ffffffff8b8ce0a0
FS: 0000555582b99500(0000) GS:ffff88808d21c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1afde3743c CR3: 0000000059f57000 CR4: 0000000000352ef0
Call Trace:
<TASK>
debug_object_assert_init+0x2db/0x380 lib/debugobjects.c:1020
debug_timer_assert_init kernel/time/timer.c:803 [inline]
debug_assert_init kernel/time/timer.c:848 [inline]
__try_to_del_timer_sync+0x29/0x3a0 kernel/time/timer.c:1457
__timer_delete_sync+0x1fe/0x2d0 kernel/time/timer.c:1620
waveform_detach+0x45/0x60 drivers/comedi/drivers/comedi_test.c:796
comedi_device_detach+0x137/0x720 drivers/comedi/drivers.c:207
comedi_device_attach+0x568/0x670 drivers/comedi/drivers.c:1000
do_devconfig_ioctl drivers/comedi/comedi_fops.c:855 [inline]
comedi_unlocked_ioctl+0x686/0xf40 drivers/comedi/comedi_fops.c:2136
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/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: 0033:0x7fa16e38e929
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:00007ffc832acc18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa16e5b5fa0 RCX: 00007fa16e38e929
RDX: 0000200000000140 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007ffc832acc70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fa16e5b5fa0 R14: 00007fa16e5b5fa0 R15: 0000000000000003
</TASK>


---
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[Hillf Danton]

> Date: Mon, 07 Jul 2025 09:31:28 -0700

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 4c06e63b9203 Merge tag 'for-6.16-rc4-tag' of git://git.ker..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16528f70580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=b29b1a0d7330d4a8
> dashboard link: https://syzkaller.appspot.com/bug?extid=eec47f88bae8951c6afd

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14a66c8c580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11528f70580000

#syz test

--- x/drivers/comedi/drivers.c
+++ y/drivers/comedi/drivers.c
@@ -994,10 +994,13 @@ int comedi_device_attach(struct comedi_d
dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
: dev->driver->driver_name;
ret = driv->attach(dev, it);
- if (ret >= 0)
+ if (ret >= 0) {
ret = comedi_device_postconfig(dev);
- if (ret < 0) {
- comedi_device_detach(dev);
+ if (ret < 0) {
+ comedi_device_detach(dev);
+ module_put(driv->module);
+ }
+ } else {
module_put(driv->module);
}
/* On success, the driver module count has been incremented. */
--

[syzbot]

Hello,

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

Reported-by: syzbot+eec47f...@syzkaller.appspotmail.com
Tested-by: syzbot+eec47f...@syzkaller.appspotmail.com

Tested on:

commit: d7b8f8e2 Linux 6.16-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14292bd4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6cfc97245100778

dashboard link: https://syzkaller.appspot.com/bug?extid=eec47f88bae8951c6afd
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

patch: https://syzkaller.appspot.com/x/patch.diff?x=13279582580000

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

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.