Re: [linux-drivers-review] [PATCH] HID: intel-ish-hid: fix NULL-ptr-deref in ishtp_bus_remove_all_clients

[srinivas pandruvada <srinivas.pandruvada@linux.intel.com>]

On Fri, 2026-01-30 at 13:25 +0800, Ryan Lin wrote:
> During a warm reset flow, the cl->device pointer may be NULL if the
> reset occurs while clients are still being enumerated. Accessing
> cl->device->reference_count without a NULL check leads to a kernel
> panic.
> 
> This issue was identified during multi-unit warm reboot stress
> clycles.
> Add a defensive NULL check for cl->device to ensure stability under
> such intensive testing conditions.
> 
> KASAN: null-ptr-deref in range [0000000000000000-0000000000000007]
> Workqueue: ish_fw_update_wq fw_reset_work_fn
> 
> Call Trace:
>  ishtp_bus_remove_all_clients+0xbe/0x130 [intel_ishtp]
>  ishtp_reset_handler+0x85/0x1a0 [intel_ishtp]
>  fw_reset_work_fn+0x8a/0xc0 [intel_ish_ipc]
> 
> Fixes: 3703f53b99e4a ("HID: intel_ish-hid: ISH Transport layer")
> Signed-off-by: Ryan Lin <ryan.lin@intel.com>

You need to use get_maintainer.pl to get all TO and CC list.

You missed 
Jiri Kosina <jikos@kernel.org>
Benjamin Tissoires <bentiss@kernel.org>


> ---
>  drivers/hid/intel-ish-hid/ishtp/bus.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/intel-ish-hid/ishtp/bus.c
> b/drivers/hid/intel-ish-hid/ishtp/bus.c
> index c3915f3a060e..b890fbf97a75 100644
> --- a/drivers/hid/intel-ish-hid/ishtp/bus.c
> +++ b/drivers/hid/intel-ish-hid/ishtp/bus.c
> @@ -730,7 +730,7 @@ void ishtp_bus_remove_all_clients(struct
> ishtp_device *ishtp_dev,
>  	spin_lock_irqsave(&ishtp_dev->cl_list_lock, flags);
>  	list_for_each_entry(cl, &ishtp_dev->cl_list, link) {
>  		cl->state = ISHTP_CL_DISCONNECTED;
> -		if (warm_reset && cl->device->reference_count)
> +		if (warm_reset && cl->device && cl->device-
> >reference_count)
>  			continue;
>  
>  		/*