[v2] drm/gud: Use kmalloc_array() instead of kmalloc()

[PATCH v2] drm/gud: Use kmalloc_array() instead of kmalloc()

Posted by Mehdi Ben Hadj Khelifa 4 months, 2 weeks ago

Replace kmalloc with kmalloc array in drm/gud/gud_pipe.c since the
calculation inside kmalloc is dynamic 'width * height' to avoid
overflow.

Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@gmail.com>
---
Changelog:

Changes since v1:
- Use of width as element count and height as size of element to
eliminate the mentionned calculation and overflow issues.

 drivers/gpu/drm/gud/gud_pipe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
index 8d548d08f127..8898dc9393fb 100644
--- a/drivers/gpu/drm/gud/gud_pipe.c
+++ b/drivers/gpu/drm/gud/gud_pipe.c
@@ -70,7 +70,7 @@ static size_t gud_xrgb8888_to_r124(u8 *dst, const struct drm_format_info *format
 	height = drm_rect_height(rect);
 	len = drm_format_info_min_pitch(format, 0, width) * height;
 
-	buf = kmalloc(width * height, GFP_KERNEL);
+	buf = kmalloc_array(width, height, GFP_KERNEL);
 	if (!buf)
 		return 0;
 
-- 
2.51.0

Re: [PATCH v2] drm/gud: Use kmalloc_array() instead of kmalloc()

Posted by Thomas Zimmermann 4 months ago

Hi

Am 23.09.25 um 10:51 schrieb Mehdi Ben Hadj Khelifa:
> Replace kmalloc with kmalloc array in drm/gud/gud_pipe.c since the
> calculation inside kmalloc is dynamic 'width * height' to avoid
> overflow.
>
> Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@gmail.com>
> ---
> Changelog:
>
> Changes since v1:
> - Use of width as element count and height as size of element to
> eliminate the mentionned calculation and overflow issues.
>
>   drivers/gpu/drm/gud/gud_pipe.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
> index 8d548d08f127..8898dc9393fb 100644
> --- a/drivers/gpu/drm/gud/gud_pipe.c
> +++ b/drivers/gpu/drm/gud/gud_pipe.c
> @@ -70,7 +70,7 @@ static size_t gud_xrgb8888_to_r124(u8 *dst, const struct drm_format_info *format
>   	height = drm_rect_height(rect);
>   	len = drm_format_info_min_pitch(format, 0, width) * height;
>   
> -	buf = kmalloc(width * height, GFP_KERNEL);
> +	buf = kmalloc_array(width, height, GFP_KERNEL);

One nitpick here: the first parameter is the number of elements and the 
second parameter is the size of an individual element. [1] So the 
arguments 'width' and 'height' should be reversed.  Please resubmit.

Best regards
Thomas

[1] 
https://elixir.bootlin.com/linux/v6.17.1/source/tools/include/linux/slab.h#L15

>   	if (!buf)
>   		return 0;
>   

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v2] drm/gud: Use kmalloc_array() instead of kmalloc()

Posted by Mehdi Ben Hadj Khelifa 4 months ago

On 10/7/25 8:45 AM, Thomas Zimmermann wrote:
> Hi
> 
> Am 23.09.25 um 10:51 schrieb Mehdi Ben Hadj Khelifa:
>> Replace kmalloc with kmalloc array in drm/gud/gud_pipe.c since the
>> calculation inside kmalloc is dynamic 'width * height' to avoid
>> overflow.
>>
>> Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@gmail.com>
>> ---
>> Changelog:
>>
>> Changes since v1:
>> - Use of width as element count and height as size of element to
>> eliminate the mentionned calculation and overflow issues.
>>
>>   drivers/gpu/drm/gud/gud_pipe.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/ 
>> gud_pipe.c
>> index 8d548d08f127..8898dc9393fb 100644
>> --- a/drivers/gpu/drm/gud/gud_pipe.c
>> +++ b/drivers/gpu/drm/gud/gud_pipe.c
>> @@ -70,7 +70,7 @@ static size_t gud_xrgb8888_to_r124(u8 *dst, const 
>> struct drm_format_info *format
>>       height = drm_rect_height(rect);
>>       len = drm_format_info_min_pitch(format, 0, width) * height;
>> -    buf = kmalloc(width * height, GFP_KERNEL);
>> +    buf = kmalloc_array(width, height, GFP_KERNEL);
> 
> One nitpick here: the first parameter is the number of elements and the 
> second parameter is the size of an individual element. [1] So the 
> arguments 'width' and 'height' should be reversed.  Please resubmit.
> 
Understood,I will be sending v3 shortly.

> Best regards
> Thomas
> 

Best Regards,
Mehdi

> [1] https://elixir.bootlin.com/linux/v6.17.1/source/tools/include/linux/ 
> slab.h#L15
> 
>>       if (!buf)
>>           return 0;
>

Re: [PATCH v2] drm/gud: Use kmalloc_array() instead of kmalloc()

Posted by Ruben Wauters 4 months ago

On Tue, 2025-09-23 at 09:51 +0100, Mehdi Ben Hadj Khelifa wrote:
> Replace kmalloc with kmalloc array in drm/gud/gud_pipe.c since the
> calculation inside kmalloc is dynamic 'width * height' to avoid
> overflow.
> 
> Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@gmail.com>

Acked-by: Ruben Wauters <rubenru09@aol.com>

> ---
> Changelog:
> 
> Changes since v1:
> - Use of width as element count and height as size of element to
> eliminate the mentionned calculation and overflow issues.
> 
>  drivers/gpu/drm/gud/gud_pipe.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
> index 8d548d08f127..8898dc9393fb 100644
> --- a/drivers/gpu/drm/gud/gud_pipe.c
> +++ b/drivers/gpu/drm/gud/gud_pipe.c
> @@ -70,7 +70,7 @@ static size_t gud_xrgb8888_to_r124(u8 *dst, const struct drm_format_info *format
>  	height = drm_rect_height(rect);
>  	len = drm_format_info_min_pitch(format, 0, width) * height;
>  
> -	buf = kmalloc(width * height, GFP_KERNEL);
> +	buf = kmalloc_array(width, height, GFP_KERNEL);
>  	if (!buf)
>  		return 0;
>