Re: [PATCH 09/12] drm/xe/pat: Report missing PAT table using structured xe_log API

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The fallback path for missing PAT tables does not abort execution, resulting in an uninitialized `xe->pat.ops` pointer being dereferenced.
--

--- Patch [9]: [PATCH 09/12] drm/xe/pat: Report missing PAT table using structured xe_log API ---
commit 08576418698c3b8696a3e32ba77fd4f46243b78e
Author: Dnyaneshwar Bhadane <[email protected]>

drm/xe/pat: Report missing PAT table using structured xe_log API

Replace drm_err() with xe_log_err() using the PAT component tag
when a platform has no matching PAT table entry.

> diff --git a/drivers/gpu/drm/xe/xe_pat.c b/drivers/gpu/drm/xe/xe_pat.c
> index 4331ef097ba0c..66a2d76ea00b5 100644
> --- a/drivers/gpu/drm/xe/xe_pat.c
> +++ b/drivers/gpu/drm/xe/xe_pat.c

[ ... ]

> @@ -686,8 +687,9 @@ void xe_pat_init_early(struct xe_device *xe)
>  		 * raise an error rather than trying to silently inherit the
>  		 * most recent platform's behavior.
>  		 */
> -		drm_err(&xe->drm, "Missing PAT table for platform with graphics version %d.%02d!\n",
> -			GRAPHICS_VER(xe), GRAPHICS_VERx100(xe) % 100);
> +		xe_log_err(xe, PAT, -EINVAL,
> +			   "Missing PAT table for platform with graphics version %d.%02d!\n",
> +			   GRAPHICS_VER(xe), GRAPHICS_VERx100(xe) % 100);
>  	}
>  
>  	xe_assert(xe, xe->pat.ops);

[Severity: High]
This is a pre-existing issue, but since you are modifying this error path,
I wanted to ask about the missing early return here.

When a platform doesn't match any known PAT table (such as when force-probing
a new unconfigured PCI ID), xe_pat_init_early() logs an error but continues
execution. This leaves xe->pat.ops uninitialized.

In debug builds, this will immediately crash on the subsequent assertion:

	xe_assert(xe, xe->pat.ops->dump);

In non-debug builds, it propagates to xe_pat_init() where it unconditionally
dereferences the uninitialized pointer:

	if (xe_gt_is_media_type(gt))
		xe->pat.ops->program_media(gt, xe->pat.table, xe->pat.n_entries);
	else
		xe->pat.ops->program_graphics(gt, xe->pat.table, xe->pat.n_entries);

Should this error path abort initialization rather than continuing with an
uninitialized xe->pat.ops pointer?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=9