linux-kernel - Re: [PATCH] drm/tiny: Use kmalloc

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Message-ID: <2025101910-dipper-suburb-1755@gregkh>
Date: Sun, 19 Oct 2025 16:34:59 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
Cc: lanzano.alex@...il.com, maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com,
	simona@...ll.ch, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, skhan@...uxfoundation.org,
	david.hunter.linux@...il.com, khalid@...nel.org,
	linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [PATCH] drm/tiny: Use kmalloc_array() instead of kmalloc()

On Sun, Oct 19, 2025 at 04:12:28PM +0100, Mehdi Ben Hadj Khelifa wrote:
> Replace kmalloc() with kmalloc_array() to correctly
> handle array allocations and benefit from built-in overflow checking[1].
> 
> [1]:https://docs.kernel.org/process/deprecated.html
> 
> Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
> ---
>  drivers/gpu/drm/tiny/repaper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/tiny/repaper.c b/drivers/gpu/drm/tiny/repaper.c
> index 4824f863fdba..290132c24ff9 100644
> --- a/drivers/gpu/drm/tiny/repaper.c
> +++ b/drivers/gpu/drm/tiny/repaper.c
> @@ -534,7 +534,7 @@ static int repaper_fb_dirty(struct drm_framebuffer *fb, const struct iosys_map *
>  	DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
>  		  epd->factored_stage_time);
>  
> -	buf = kmalloc(fb->width * fb->height / 8, GFP_KERNEL);
> +	buf = kmalloc_array(fb->height / 8, fb->width, GFP_KERNEL);

This isn't an array, so this function change doesn't seem to make much
sense, right?  The size should have already been checked earlier in the
call change to be correct.

thanks,

greg k-h