Re: [PATCH] cxl/region: Use %pa printk format to emit resource_size_t

[Dave Jiang <dave.jiang@intel.com>]

On 10/14/25 12:31 AM, Alison Schofield wrote:
> KASAN reports a stack-out-of-bounds access in validate_region_offset()
> while running the cxl-poison.sh unit test because the printk format
> specifier, %pr format, is not a match for the resource_size_t type of
> the variables. %pr expects struct resource pointers and attempts to
> dereference the structure fields, reading beyond the bounds of the
> stack variables.
> 
> Since these messages emit  an 'A exceeds B' type of message, keep
> the resource_size_t's and use the %pa specifier to be architecture
> safe.
> 
> BUG: KASAN: stack-out-of-bounds in resource_string.isra.0+0xe9a/0x1690
> [] Read of size 8 at addr ffff88800a7afb40 by task bash/1397
> ...
> [] The buggy address belongs to stack of task bash/1397
> []  and is located at offset 56 in frame:
> []  validate_region_offset+0x0/0x1c0 [cxl_core]
> 
> Fixes: c3dd67681c70 ("cxl/region: Add inject and clear poison by region offset")
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>> ---
>  drivers/cxl/core/region.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index e14c1d305b22..4e567f7e06bc 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3666,14 +3666,14 @@ static int validate_region_offset(struct cxl_region *cxlr, u64 offset)
>  
>  	if (offset < p->cache_size) {
>  		dev_err(&cxlr->dev,
> -			"Offset %#llx is within extended linear cache %pr\n",
> +			"Offset %#llx is within extended linear cache %pa\n",
>  			offset, &p->cache_size);
>  		return -EINVAL;
>  	}
>  
>  	region_size = resource_size(p->res);
>  	if (offset >= region_size) {
> -		dev_err(&cxlr->dev, "Offset %#llx exceeds region size %pr\n",
> +		dev_err(&cxlr->dev, "Offset %#llx exceeds region size %pa\n",
>  			offset, &region_size);
>  		return -EINVAL;
>  	}
> 
> base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787