[syzbot] [usb?] BUG: corrupted list in usb_hcd_link_urb_to_ep (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6fab32bb6508 MAINTAINERS: add Mark Brown as a linux-next m..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d0ed42580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d1ce99afe6f71855
dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6fab32bb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/38b1c3a2c170/vmlinux-6fab32bb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6a6377b85494/bzImage-6fab32bb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e69c25...@syzkaller.appspotmail.com

input: CM109 USB driver as /devices/platform/dummy_hcd.6/usb11/11-1/11-1:0.8/input/input39
list_add double add: new=ffff888047968c18, prev=ffff888047968c18, next=ffff88803609c078.
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:35!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 3 UID: 0 PID: 34 Comm: kworker/3:0 Not tainted syzkaller #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
Workqueue: usb_hub_wq hub_event
RIP: 0010:__list_add_valid_or_report+0x143/0x190 lib/list_debug.c:35
Code: 89 f1 48 c7 c7 c0 6e f0 8b 48 89 ee e8 a6 0d ef fc 90 0f 0b 48 89 f2 48 89 e9 4c 89 e6 48 c7 c7 40 6f f0 8b e8 8e 0d ef fc 90 <0f> 0b 48 89 f7 48 89 34 24 e8 1f 46 79 fd 48 8b 34 24 e9 07 ff ff
RSP: 0018:ffffc900006ded50 EFLAGS: 00010086
RAX: 0000000000000058 RBX: ffff888047968c00 RCX: ffffffff819b7079
RDX: 0000000000000000 RSI: ffffffff819beba6 RDI: 0000000000000005
RBP: ffff88803609c078 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000002 R11: 0000000000002b91 R12: ffff888047968c18
R13: ffff88803609c080 R14: 0000000000000000 R15: ffff888047968c18
FS: 0000000000000000(0000) GS:ffff8880d6d0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3c92d9 CR3: 00000000320a4000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__list_add_valid include/linux/list.h:96 [inline]
__list_add include/linux/list.h:158 [inline]
list_add_tail include/linux/list.h:191 [inline]
usb_hcd_link_urb_to_ep+0x220/0x3a0 drivers/usb/core/hcd.c:1158
dummy_urb_enqueue+0x2a7/0x920 drivers/usb/gadget/udc/dummy_hcd.c:1288
usb_hcd_submit_urb+0x25b/0x1c60 drivers/usb/core/hcd.c:1546
usb_submit_urb+0x89f/0x1990 drivers/usb/core/urb.c:587
cm109_input_open+0x27a/0x490 drivers/input/misc/cm109.c:566
input_open_device+0x24c/0x3d0 drivers/input/input.c:601
kbd_connect+0x103/0x160 drivers/tty/vt/keyboard.c:1584
input_attach_handler.isra.0+0x176/0x250 drivers/input/input.c:994
input_register_device+0xab9/0x1180 drivers/input/input.c:2378
cm109_usb_probe+0x122f/0x17c0 drivers/input/misc/cm109.c:797
usb_probe_interface+0x303/0xa40 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:581 [inline]
really_probe+0x241/0xa90 drivers/base/dd.c:659
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:801
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831
__device_attach_driver+0x1df/0x310 drivers/base/dd.c:959
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:462
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1031
bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:537
device_add+0x1148/0x1aa0 drivers/base/core.c:3689
usb_set_configuration+0x1187/0x1e20 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0xb1/0x110 drivers/usb/core/generic.c:250
usb_probe_device+0xef/0x3e0 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:581 [inline]
really_probe+0x241/0xa90 drivers/base/dd.c:659
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:801
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831
__device_attach_driver+0x1df/0x310 drivers/base/dd.c:959
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:462
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1031
bus_probe_device+0x17f/0x1c0 drivers/base/bus.c:537
device_add+0x1148/0x1aa0 drivers/base/core.c:3689
usb_new_device+0xd07/0x1a60 drivers/usb/core/hub.c:2694
hub_port_connect drivers/usb/core/hub.c:5566 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
port_event drivers/usb/core/hub.c:5870 [inline]
hub_event+0x2f34/0x4fe0 drivers/usb/core/hub.c:5952
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_add_valid_or_report+0x143/0x190 lib/list_debug.c:35
Code: 89 f1 48 c7 c7 c0 6e f0 8b 48 89 ee e8 a6 0d ef fc 90 0f 0b 48 89 f2 48 89 e9 4c 89 e6 48 c7 c7 40 6f f0 8b e8 8e 0d ef fc 90 <0f> 0b 48 89 f7 48 89 34 24 e8 1f 46 79 fd 48 8b 34 24 e9 07 ff ff
RSP: 0018:ffffc900006ded50 EFLAGS: 00010086
RAX: 0000000000000058 RBX: ffff888047968c00 RCX: ffffffff819b7079
RDX: 0000000000000000 RSI: ffffffff819beba6 RDI: 0000000000000005
RBP: ffff88803609c078 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000002 R11: 0000000000002b91 R12: ffff888047968c18
R13: ffff88803609c080 R14: 0000000000000000 R15: ffff888047968c18
FS: 0000000000000000(0000) GS:ffff8880d6d0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3c92d9 CR3: 00000000320a4000 CR4: 0000000000352ef0


---
This report is generated by a bot. It may contain errors.
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syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
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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:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: aacb0a6d604a Merge tag 'pmdomain-v6.19-rc3' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16578f92580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765

dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1627369a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d70d8ecc100f/disk-aacb0a6d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/905258eeaaeb/vmlinux-aacb0a6d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/92f24a766750/bzImage-aacb0a6d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e69c25...@syzkaller.appspotmail.com

list_add double add: new=ffff888028dc3118, prev=ffff888028dc3118, next=ffff8880761de078.

------------[ cut here ]------------
kernel BUG at lib/list_debug.c:35!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI

CPU: 0 UID: 0 PID: 7322 Comm: syz.2.605 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025

RIP: 0010:__list_add_valid_or_report+0x143/0x190 lib/list_debug.c:35

Code: 89 f1 48 c7 c7 c0 b6 f2 8b 48 89 ee e8 d6 9a e7 fc 90 0f 0b 48 89 f2 48 89 e9 4c 89 e6 48 c7 c7 40 b7 f2 8b e8 be 9a e7 fc 90 <0f> 0b 48 89 f7 48 89 34 24 e8 cf db 73 fd 48 8b 34 24 e9 07 ff ff
RSP: 0018:ffffc90004ca7580 EFLAGS: 00010086
RAX: 0000000000000058 RBX: ffff888028dc3100 RCX: ffffffff819c8fa5
RDX: 0000000000000000 RSI: ffffffff819d0b89 RDI: 0000000000000005
RBP: ffff8880761de078 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000004 R11: 0000000000000001 R12: ffff888028dc3118
R13: ffff8880761de080 R14: 0000000000000000 R15: ffff888028dc3118
FS: 00007fa72ab066c0(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000200000002000 CR3: 000000007860f000 CR4: 00000000003526f0

Call Trace:
<TASK>
__list_add_valid include/linux/list.h:96 [inline]
__list_add include/linux/list.h:158 [inline]
list_add_tail include/linux/list.h:191 [inline]
usb_hcd_link_urb_to_ep+0x220/0x3a0 drivers/usb/core/hcd.c:1158
dummy_urb_enqueue+0x2a7/0x920 drivers/usb/gadget/udc/dummy_hcd.c:1288

usb_hcd_submit_urb+0x25b/0x1cf0 drivers/usb/core/hcd.c:1546
usb_submit_urb+0x899/0x1970 drivers/usb/core/urb.c:587
cm109_submit_buzz_toggle+0xd9/0x180 drivers/input/misc/cm109.c:351
cm109_toggle_buzzer_async drivers/input/misc/cm109.c:484 [inline]
cm109_input_ev+0x23d/0x280 drivers/input/misc/cm109.c:615
input_event_dispose drivers/input/input.c:322 [inline]
input_handle_event+0x151/0x14d0 drivers/input/input.c:370
input_inject_event+0x1e8/0x3b0 drivers/input/input.c:424
kd_sound_helper+0x17a/0x280 drivers/tty/vt/keyboard.c:256
input_handler_for_each_handle+0xd7/0x250 drivers/input/input.c:2520
kd_mksound+0x88/0x130 drivers/tty/vt/keyboard.c:280
handle_ascii drivers/tty/vt/vt.c:2327 [inline]
do_con_trol drivers/tty/vt/vt.c:2644 [inline]
do_con_write+0x3246/0x8280 drivers/tty/vt/vt.c:3228
con_write+0x23/0xb0 drivers/tty/vt/vt.c:3565
process_output_block drivers/tty/n_tty.c:557 [inline]
n_tty_write+0x434/0x1280 drivers/tty/n_tty.c:2366
iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
file_tty_write.constprop.0+0x503/0x9b0 drivers/tty/tty_io.c:1081
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa729b8f749
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:00007fa72ab06038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa729de5fa0 RCX: 00007fa729b8f749
RDX: 0000000000001006 RSI: 0000200000001980 RDI: 0000000000000005
RBP: 00007fa729c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa729de6038 R14: 00007fa729de5fa0 R15: 00007ffdb843d7a8

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_add_valid_or_report+0x143/0x190 lib/list_debug.c:35

Code: 89 f1 48 c7 c7 c0 b6 f2 8b 48 89 ee e8 d6 9a e7 fc 90 0f 0b 48 89 f2 48 89 e9 4c 89 e6 48 c7 c7 40 b7 f2 8b e8 be 9a e7 fc 90 <0f> 0b 48 89 f7 48 89 34 24 e8 cf db 73 fd 48 8b 34 24 e9 07 ff ff
RSP: 0018:ffffc90004ca7580 EFLAGS: 00010086
RAX: 0000000000000058 RBX: ffff888028dc3100 RCX: ffffffff819c8fa5
RDX: 0000000000000000 RSI: ffffffff819d0b89 RDI: 0000000000000005
RBP: ffff8880761de078 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000004 R11: 0000000000000001 R12: ffff888028dc3118
R13: ffff8880761de080 R14: 0000000000000000 R15: ffff888028dc3118
FS: 00007fa72ab066c0(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000200000002000 CR3: 000000007860f000 CR4: 00000000003526f0


---
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.

[Hillf Danton]

> Date: Sat, 03 Jan 2026 23:03:24 -0800

> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: aacb0a6d604a Merge tag 'pmdomain-v6.19-rc3' of git://git.k..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16578f92580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765
> dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
> compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1627369a580000

#syz test

--- x/drivers/input/misc/cm109.c
+++ y/drivers/input/misc/cm109.c
@@ -562,15 +562,18 @@ static int cm109_input_open(struct input
dev->ctl_data->byte[HID_OR2] = dev->keybit;
dev->ctl_data->byte[HID_OR3] = 0x00;

+ spin_lock_irq(&dev->ctl_submit_lock);
dev->ctl_urb_pending = 1;
- error = usb_submit_urb(dev->urb_ctl, GFP_KERNEL);
+ error = usb_submit_urb(dev->urb_ctl, GFP_ATOMIC);
if (!error) {
dev->open = 1;
+ spin_unlock_irq(&dev->ctl_submit_lock);
return 0;
}
+ dev->ctl_urb_pending = 0;
+ spin_unlock_irq(&dev->ctl_submit_lock);
}

- dev->ctl_urb_pending = 0;
usb_autopm_put_interface(dev->intf);

dev_err(&dev->intf->dev, "%s: usb_submit_urb (urb_ctl) failed %d\n",
--

[syzbot]

Hello,

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

Reported-by: syzbot+e69c25...@syzkaller.appspotmail.com
Tested-by: syzbot+e69c25...@syzkaller.appspotmail.com

Tested on:

commit: 3609fa95 Merge tag 'devicetree-fixes-for-6.19-2' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=151ecf92580000

kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765
dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=11414074580000

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

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 2b763db0c276 Add linux-next specific files for 20260703
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11f96ffe580000
kernel config: https://syzkaller.appspot.com/x/.config?x=bc069df559a09463
dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14a9dffe580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=103d8b1c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/48dad133dd60/disk-2b763db0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/df274fd385d1/vmlinux-2b763db0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f3a54c0c16ec/bzImage-2b763db0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e69c25...@syzkaller.appspotmail.com

list_add double add: new=ffff88801bf49818, prev=ffff88801bf49818, next=ffff888040cc4078.
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:37!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 7510 Comm: syz.2.757 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__list_add_valid_or_report+0xa5/0x130 lib/list_debug.c:35
Code: 74 12 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d e9 02 d7 79 06 cc 48 c7 c7 60 9c cb 8b 4c 89 fe 4c 89 f2 48 89 d9 e8 6c a0 50 fc 90 <0f> 0b 48 c7 c7 40 9a cb 8b e8 5d a0 50 fc 90 0f 0b 48 c7 c7 00 9b
RSP: 0018:ffffc90005a3f320 EFLAGS: 00010246
RAX: 0000000000000058 RBX: ffff888040cc4078 RCX: aa19a771139add00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff11008198810 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff52000b47e15 R12: 1ffff110037e9303
R13: dffffc0000000000 R14: ffff88801bf49818 R15: ffff88801bf49818
FS: 00007fadf887e6c0(0000) GS:ffff888125b00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f0f79a3b540 CR3: 000000003c4c0000 CR4: 00000000003526f0

Call Trace:
<TASK>
__list_add_valid include/linux/list.h:96 [inline]
__list_add include/linux/list.h:158 [inline]
list_add_tail include/linux/list.h:191 [inline]

usb_hcd_link_urb_to_ep+0x1d2/0x330 drivers/usb/core/hcd.c:1154
dummy_urb_enqueue+0x299/0x760 drivers/usb/gadget/udc/dummy_hcd.c:1292
usb_hcd_submit_urb+0x322/0x1b40 drivers/usb/core/hcd.c:1542
cm109_submit_buzz_toggle drivers/input/misc/cm109.c:351 [inline]
cm109_toggle_buzzer_async drivers/input/misc/cm109.c:484 [inline]
cm109_input_ev+0x1d1/0x3b0 drivers/input/misc/cm109.c:615
input_event_dispose+0x80/0x6b0 drivers/input/input.c:322
input_inject_event+0x1fa/0x310 drivers/input/input.c:424
kd_sound_helper+0x101/0x210 drivers/tty/vt/keyboard.c:257
input_handler_for_each_handle+0x101/0x1c0 drivers/input/input.c:2540
kd_mksound+0x96/0x130 drivers/tty/vt/keyboard.c:281
handle_ascii drivers/tty/vt/vt.c:2382 [inline]
do_con_trol drivers/tty/vt/vt.c:2699 [inline]
do_con_write+0x2f5a/0x5540 drivers/tty/vt/vt.c:3325
con_write+0x31/0x2e0 drivers/tty/vt/vt.c:3661
process_output_block drivers/tty/n_tty.c:557 [inline]
n_tty_write+0xd4f/0x11e0 drivers/tty/n_tty.c:2366
iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
file_tty_write+0x50b/0x980 drivers/tty/tty_io.c:1081
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61e/0xbb0 fs/read_write.c:687
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fadf921de59
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:00007fadf887e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fadf94a5fa0 RCX: 00007fadf921de59
RDX: 000000000000045c RSI: 00002000000004c0 RDI: 0000000000000005
RBP: 00007fadf92b3e6f R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fadf94a6038 R14: 00007fadf94a5fa0 R15: 00007ffcbb190028

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---

RIP: 0010:__list_add_valid_or_report+0xa5/0x130 lib/list_debug.c:35
Code: 74 12 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d e9 02 d7 79 06 cc 48 c7 c7 60 9c cb 8b 4c 89 fe 4c 89 f2 48 89 d9 e8 6c a0 50 fc 90 <0f> 0b 48 c7 c7 40 9a cb 8b e8 5d a0 50 fc 90 0f 0b 48 c7 c7 00 9b
RSP: 0018:ffffc90005a3f320 EFLAGS: 00010246
RAX: 0000000000000058 RBX: ffff888040cc4078 RCX: aa19a771139add00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff11008198810 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff52000b47e15 R12: 1ffff110037e9303
R13: dffffc0000000000 R14: ffff88801bf49818 R15: ffff88801bf49818
FS: 00007fadf887e6c0(0000) GS:ffff888125b00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f0f79a3b540 CR3: 000000003c4c0000 CR4: 00000000003526f0

[Alan Stern]

On Sun, Jul 05, 2026 at 03:23:29AM -0700, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 2b763db0c276 Add linux-next specific files for 20260703
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=11f96ffe580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=bc069df559a09463
> dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
> compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14a9dffe580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=103d8b1c580000

This driver has a lot of bugs. This is a partial fix for some of them.

#syz test: linux-next 2b763db0c276

Index: usb-devel/drivers/input/misc/cm109.c
===================================================================
--- usb-devel.orig/drivers/input/misc/cm109.c
+++ usb-devel/drivers/input/misc/cm109.c
@@ -349,10 +349,14 @@ static void cm109_submit_buzz_toggle(str
dev->ctl_data->byte[HID_OR0] &= ~BUZZER_ON;

error = usb_submit_urb(dev->urb_ctl, GFP_ATOMIC);

- if (error)
+ if (error) {

dev_err(&dev->intf->dev,
"%s: usb_submit_urb (urb_ctl) failed %d\n",

__func__, error);
+ } else {
+ dev->ctl_urb_pending = 1;
+ dev->buzzer_pending = 0;
+ }
}

static void cm109_submit_ctl(struct cm109_dev *dev)
@@ -361,9 +365,7 @@ static void cm109_submit_ctl(struct cm10

guard(spinlock_irqsave)(&dev->ctl_submit_lock);

- dev->irq_urb_pending = 0;
-
- if (unlikely(dev->shutdown))
+ if (unlikely(dev->shutdown) || dev->ctl_urb_pending)
return;

if (dev->buzzer_state)
@@ -374,14 +376,15 @@ static void cm109_submit_ctl(struct cm10
dev->ctl_data->byte[HID_OR1] = dev->keybit;
dev->ctl_data->byte[HID_OR2] = dev->keybit;

- dev->buzzer_pending = 0;
- dev->ctl_urb_pending = 1;
-
error = usb_submit_urb(dev->urb_ctl, GFP_ATOMIC);
- if (error)
+ if (error) {

dev_err(&dev->intf->dev,
"%s: usb_submit_urb (urb_ctl) failed %d\n",

__func__, error);
+ } else {
+ dev->ctl_urb_pending = 1;
+ dev->buzzer_pending = 0;
+ }
}

/*
@@ -428,6 +431,7 @@ static void cm109_urb_irq_callback(struc
}

out:
+ dev->irq_urb_pending = 0;
cm109_submit_ctl(dev);
}

@@ -458,17 +462,16 @@ static void cm109_urb_ctl_callback(struc
return;

if (dev->buzzer_pending || status) {
- dev->buzzer_pending = 0;
- dev->ctl_urb_pending = 1;
cm109_submit_buzz_toggle(dev);
} else if (likely(!dev->irq_urb_pending)) {
/* ask for key data */
- dev->irq_urb_pending = 1;
error = usb_submit_urb(dev->urb_irq, GFP_ATOMIC);
if (error)
dev_err(&dev->intf->dev,
"%s: usb_submit_urb (urb_irq) failed %d\n",
__func__, error);
+ else
+ dev->irq_urb_pending = 1;
}
}

@@ -480,7 +483,6 @@ static void cm109_toggle_buzzer_async(st
/* URB completion will resubmit */
dev->buzzer_pending = 1;
} else {
- dev->ctl_urb_pending = 1;
cm109_submit_buzz_toggle(dev);
}
}

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: 2b763db0 Add linux-next specific files for 20260703
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=15586b39580000

kernel config: https://syzkaller.appspot.com/x/.config?x=bc069df559a09463
dashboard link: https://syzkaller.appspot.com/bug?extid=e69c25cf38a53d0cf64c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=13aef31e580000

[Alan Stern]

The console output says, in its entirety:

-----------------------------------------------------------------------------

ci-upstream-rust-kasan-gce-test-job/strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ci-upstream-rust-kasan-gce-test-job/syz-execprog -executor=ci-upstream-rust-kasan-gce-test-job/syz-executor -arch=amd64 -sandbox=none -procs=4 -repeat=0 -threaded=true -collide=false -optional=slowdown=1:sandbox_arg=0:type=gce ci-upstream-rust-kasan-gce-test-job/syzkaller4044572343

<...>
Warning: Permanently added '10.128.0.74' (ED25519) to the list of known hosts.
FATAL: kernel too old
[ 132.897272][ T1336] ieee802154 phy0 wpan0: encryption failed: -22
[ 132.897384][ T1336] ieee802154 phy1 wpan1: encryption failed: -22

-----------------------------------------------------------------------------

What can I do about this?

Alan Stern