Re: [PATCH][next] drm/i915/guc: Use struct_size() helper in kmalloc()

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 25/01/2022 18:07, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
> 
> Also, address the following sparse warnings:
> drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c:792:23: warning: using sizeof on a flexible structure
> 
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> index aa6dd6415202..e352a1aad228 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> @@ -789,7 +789,7 @@ static struct ct_incoming_msg *ct_alloc_msg(u32 num_dwords)
>   {
>   	struct ct_incoming_msg *msg;
>   
> -	msg = kmalloc(sizeof(*msg) + sizeof(u32) * num_dwords, GFP_ATOMIC);
> +	msg = kmalloc(struct_size(msg, msg, num_dwords), GFP_ATOMIC);
>   	if (msg)
>   		msg->size = num_dwords;
>   	return msg;
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Thanks for the patch, will merge shortly.

Regards,

Tvrtko