[syzbot] Kernel panic in pcipcwd_get_status due to simulated overheat

[王志]

syzbot has found the following issue on:

HEAD commit: 6.18.0 (custom build)
git tree: linux-stable
console output: (see below)
kernel config: (attached)

---

pcwd_pci: Card timer not enabled
pcwd_pci: Unexpected close, not stopping watchdog!
pcwd_pci: Card timer not enabled
pcwd_pci: Unexpected close, not stopping watchdog!
pcwd_pci: Card timer not enabled
Kernel panic - not syncing: pcwd_pci: Temperature overheat trip!
CPU: 0 UID: 0 PID: 2722 Comm: syz.0.86 Not tainted 6.18.0 #3 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
__dump_stack home/wmy/Fuzzer/third_tool/linux-6.18/lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x3d/0x140 home/wmy/Fuzzer/third_tool/linux-6.18/lib/dump_stack.c:120
vpanic+0x66f/0x6e0 home/wmy/Fuzzer/third_tool/linux-6.18/kernel/panic.c:489
panic+0xc7/0xd0 home/wmy/Fuzzer/third_tool/linux-6.18/kernel/panic.c:626
pcipcwd_get_status home/wmy/Fuzzer/third_tool/linux-6.18/drivers/watchdog/pcwd_pci.c:348 [inline] [pcwd_pci]
pcipcwd_get_status.isra.0+0x11f/0x140 home/wmy/Fuzzer/third_tool/linux-6.18/drivers/watchdog/pcwd_pci.c:337 [pcwd_pci]
pcipcwd_ioctl+0x3e1/0x4f0 home/wmy/Fuzzer/third_tool/linux-6.18/drivers/watchdog/pcwd_pci.c:485 [pcwd_pci]
vfs_ioctl home/wmy/Fuzzer/third_tool/linux-6.18/fs/ioctl.c:51 [inline]
__do_sys_ioctl home/wmy/Fuzzer/third_tool/linux-6.18/fs/ioctl.c:597 [inline]
__se_sys_ioctl home/wmy/Fuzzer/third_tool/linux-6.18/fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x194/0x210 home/wmy/Fuzzer/third_tool/linux-6.18/fs/ioctl.c:583
do_syscall_x64 home/wmy/Fuzzer/third_tool/linux-6.18/arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc6/0x390 home/wmy/Fuzzer/third_tool/linux-6.18/arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f372bbe059d
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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:00007f372a61ef98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f372be55fa0 RCX: 00007f372bbe059d
RDX: 0000000000000007 RSI: 0000000080045701 RDI: 0000000000000003
RBP: 00007f372bc7e078 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f372be56038 R14: 00007f372be55fa0 R15: 00007f372a5ff000
</TASK>
Shutting down cpus with NMI
Kernel Offset: disabled

[Guenter Roeck]

On Thu, Jan 08, 2026 at 10:50:35AM +0800, 王志 wrote:
> syzbot has found the following issue on:
>
> HEAD commit: 6.18.0 (custom build)
> git tree: linux-stable
> console output: (see below)
> kernel config: (attached)
>
> ---
>
> pcwd_pci: Card timer not enabled
> pcwd_pci: Unexpected close, not stopping watchdog!
> pcwd_pci: Card timer not enabled
> pcwd_pci: Unexpected close, not stopping watchdog!
> pcwd_pci: Card timer not enabled
> Kernel panic - not syncing: pcwd_pci: Temperature overheat trip!

You mean syzbot now complains that a driver is doing exactly what
it is supposed to be doing ? Really ?

It is not surprising that more and more people consider syzbot reports
to be just noise.

Guenter

[Aleksandr Nogikh]

Please note that it was not a report from syzbot itself.

>
> Guenter
>