[PATCH] Documentation: power: Use kcalloc() instead of kzalloc()

[PATCH] Documentation: power: Use kcalloc() instead of kzalloc()

[Erick Archer]

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, in the example code use the purpose specific kcalloc() function
instead of the argument size * count in the kzalloc() function.

Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/162
Signed-off-by: Erick Archer <erick.archer@gmx.com>
---
 Documentation/power/opp.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/power/opp.rst b/Documentation/power/opp.rst
index a7c03c470980..1b7f1d854f14 100644
--- a/Documentation/power/opp.rst
+++ b/Documentation/power/opp.rst
@@ -305,7 +305,7 @@ dev_pm_opp_get_opp_count
 	 {
 		/* Do things */
 		num_available = dev_pm_opp_get_opp_count(dev);
-		speeds = kzalloc(sizeof(u32) * num_available, GFP_KERNEL);
+		speeds = kcalloc(num_available, sizeof(u32), GFP_KERNEL);
 		/* populate the table in increasing order */
 		freq = 0;
 		while (!IS_ERR(opp = dev_pm_opp_find_freq_ceil(dev, &freq))) {
--
2.25.1

Re: [PATCH] Documentation: power: Use kcalloc() instead of kzalloc()

[Erick Archer]

On Sat, Jan 20, 2024 at 01:05:27PM +0100, Erick Archer wrote:
> As noted in the "Deprecated Interfaces, Language Features, Attributes,
> and Conventions" documentation [1], size calculations (especially
> multiplication) should not be performed in memory allocator (or similar)
> function arguments due to the risk of them overflowing. This could lead
> to values wrapping around and a smaller allocation being made than the
> caller was expecting. Using those allocations could lead to linear
> overflows of heap memory and other misbehaviors.
>
> So, in the example code use the purpose specific kcalloc() function
> instead of the argument size * count in the kzalloc() function.
>
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/162
> Signed-off-by: Erick Archer <erick.archer@gmx.com>

Hi,

Drop this patch as a new version has been sent to change at the
same time the translations.

Thanks,
Erick

> ---
>  Documentation/power/opp.rst | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/power/opp.rst b/Documentation/power/opp.rst
> index a7c03c470980..1b7f1d854f14 100644
> --- a/Documentation/power/opp.rst
> +++ b/Documentation/power/opp.rst
> @@ -305,7 +305,7 @@ dev_pm_opp_get_opp_count
>  	 {
>  		/* Do things */
>  		num_available = dev_pm_opp_get_opp_count(dev);
> -		speeds = kzalloc(sizeof(u32) * num_available, GFP_KERNEL);
> +		speeds = kcalloc(num_available, sizeof(u32), GFP_KERNEL);
>  		/* populate the table in increasing order */
>  		freq = 0;
>  		while (!IS_ERR(opp = dev_pm_opp_find_freq_ceil(dev, &freq))) {
> --
> 2.25.1
>