[PATCH v2] sched/topology: change kzalloc to kcalloc

[PATCH v2] sched/topology: change kzalloc to kcalloc

[Ethan Carter Edwards]

We are replacing any instances of kzalloc(size * count, ...) with
kcalloc(count, size, ...) due to risk of overflow [1].

[1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
Link: https://github.com/KSPP/linux/issues/162

Signed-off-by: Ethan Carter Edwards <ethan@ethancedwards.com>
---
 V2: fix email client formatting.
 kernel/sched/topology.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 9748a4c8d668..17eb12819563 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1920,7 +1920,7 @@ void sched_init_numa(int offline_node)
 	 */
 	sched_domains_numa_levels = 0;
 
-	masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL);
+	masks = kcalloc(nr_levels, sizeof(void *), GFP_KERNEL);
 	if (!masks)
 		return;
 
@@ -1929,7 +1929,7 @@ void sched_init_numa(int offline_node)
 	 * CPUs of nodes that are that many hops away from us.
 	 */
 	for (i = 0; i < nr_levels; i++) {
-		masks[i] = kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
+		masks[i] = kcalloc(nr_node_ids, sizeof(void *), GFP_KERNEL);
 		if (!masks[i])
 			return;
 
-- 
2.47.1

Re: [PATCH v2] sched/topology: change kzalloc to kcalloc

[Ethan Carter Edwards]

I wanted to check in on this. Anything I need to change?

Thanks,
Ethan

On 25/01/19 01:23PM, Ethan Carter Edwards wrote:
> We are replacing any instances of kzalloc(size * count, ...) with
> kcalloc(count, size, ...) due to risk of overflow [1].
> 
> [1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
> Link: https://github.com/KSPP/linux/issues/162
> 
> Signed-off-by: Ethan Carter Edwards <ethan@ethancedwards.com>
> ---
>  V2: fix email client formatting.
>  kernel/sched/topology.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index 9748a4c8d668..17eb12819563 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -1920,7 +1920,7 @@ void sched_init_numa(int offline_node)
>  	 */
>  	sched_domains_numa_levels = 0;
>  
> -	masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL);
> +	masks = kcalloc(nr_levels, sizeof(void *), GFP_KERNEL);
>  	if (!masks)
>  		return;
>  
> @@ -1929,7 +1929,7 @@ void sched_init_numa(int offline_node)
>  	 * CPUs of nodes that are that many hops away from us.
>  	 */
>  	for (i = 0; i < nr_levels; i++) {
> -		masks[i] = kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
> +		masks[i] = kcalloc(nr_node_ids, sizeof(void *), GFP_KERNEL);
>  		if (!masks[i])
>  			return;
>  
> -- 
> 2.47.1
> 

Re: [PATCH v2] sched/topology: change kzalloc to kcalloc

[Markus Elfring]

> We are replacing any instances of kzalloc(size * count, ...) with
> kcalloc(count, size, ...) due to risk of overflow [1].

* See also:
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.13#n94

* How do you think about to use a summary phrase like “Replace two kzalloc() calls
  by kcalloc() in sched_init_numa()”?

* Would you be looking for any coccicheck extensions accordingly?

Regards,
Markus