Re: [PATCH] cxl/ras: Fix match_memdev_by_parent() pointer type mismatch

[Dave Jiang]

On 6/8/26 3:43 PM, Terry Bowman wrote:
> bus_find_device() passes its data argument directly to the match
> function as a const void *. match_memdev_by_parent() compares
> dev->parent against this pointer:
> 
>     dev->parent == uport
> 
> cxlmd->dev.parent is set in cxl_memdev_alloc() as:
> 
>     dev->parent = cxlds->dev;  /* cxlds->dev == &pdev->dev */
> 
> So cxlmd->dev.parent holds a struct device * pointing to &pdev->dev.
> However, bus_find_device() is called with pdev (struct pci_dev *)
> rather than &pdev->dev (struct device *). Since struct pci_dev does
> not begin with struct device, the two pointer values differ, causing
> the comparison to always evaluate false.
> 
> As a result, cxl_cper_handle_prot_err() silently drops every CPER
> error report for CXL endpoint devices -- bus_find_device() always
> returns NULL and the function returns early without emitting any
> kernel trace event.
> 
> Fix by passing &pdev->dev instead of pdev.
> 
> Fixes: 3c70ec71abda ("cxl/ras: Fix CPER handler device confusion")
> Reported-by: Sashiko <sashiko@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>

Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>

Probably good to keep the original line wrapping. I can fix that on apply.


> ---
>  drivers/cxl/core/ras.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
> index 006c6ffc2f56..7ec2dab152a7 100644
> --- a/drivers/cxl/core/ras.c
> +++ b/drivers/cxl/core/ras.c
> @@ -94,8 +94,7 @@ void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
>  	if (!pdev->dev.driver)
>  		return;
>  
> -	struct device *mem_dev __free(put_device) = bus_find_device(
> -		&cxl_bus_type, NULL, pdev, match_memdev_by_parent);
> +	struct device *mem_dev __free(put_device) = bus_find_device(&cxl_bus_type, NULL, &pdev->dev, match_memdev_by_parent);
>  	if (!mem_dev)
>  		return;
>