Re: [PATCH v3 01/36] drm/xe: Add NULL checks to scratch LRC allocation

["Lis, Tomasz" <tomasz.lis@intel.com>]

[-- Attachment #1: Type: text/plain, Size: 1567 bytes --]


On 9/29/2025 4:55 AM, Matthew Brost wrote:
> kmalloc can fail, the returned value must have a NULL check.
>
> Fixes: 168b5867318b ("drm/xe/vf: Refresh utilization buffer during migration recovery")
> Signed-off-by: Matthew Brost<matthew.brost@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_lrc.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index 47e9df775072..e1bc102a6cae 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -1303,8 +1303,11 @@ static int setup_wa_bb(struct xe_lrc *lrc, struct xe_hw_engine *hwe)
>   	u32 *buf = NULL;
>   	int ret;
>   
> -	if (lrc->bo->vmap.is_iomem)
> +	if (lrc->bo->vmap.is_iomem) {
>   		buf = kmalloc(LRC_WA_BB_SIZE, GFP_KERNEL);
> +		if (!buf)
> +			return -ENOMEM;
> +	}
>   
>   	ret = xe_lrc_setup_wa_bb_with_scratch(lrc, hwe, buf);

xe_lrc_setup_wa_bb_with_scratch()->setup_bo() handles the ENOMEM return, there was no bug.

>   
> @@ -1347,8 +1350,11 @@ setup_indirect_ctx(struct xe_lrc *lrc, struct xe_hw_engine *hwe)
>   	if (xe_gt_WARN_ON(lrc->gt, !state.funcs))
>   		return 0;
>   
> -	if (lrc->bo->vmap.is_iomem)
> +	if (lrc->bo->vmap.is_iomem) {
>   		state.buffer = kmalloc(state.max_size, GFP_KERNEL);
> +		if (!state.buffer)
> +			return -ENOMEM;
> +	}
>   
>   	ret = setup_bo(&state);

setup_bo() does another check with ENOMEM return, no bug here as well. 
Also, with how setup_bo() exits, it ignores lack of allocation in case 
it won't be used anyway. -Tomasz

>   	if (ret) {

[-- Attachment #2: Type: text/html, Size: 2609 bytes --]