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

[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+eec47f88bae8951c6afd@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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Re: [syzbot] [kernel?] INFO: trying to register non-static key in waveform_detach

[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. */
--

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

[syzbot]

Hello,

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

Reported-by: syzbot+eec47f88bae8951c6afd@syzkaller.appspotmail.com
Tested-by: syzbot+eec47f88bae8951c6afd@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.