Re: [PATCH 1/2] mm: vmpressure: don't need call kfree if kstrndup fails

[Yang Shi]

On 2/12/20 8:48 PM, Andrew Morton wrote:
> On Wed, 12 Feb 2020 19:14:27 -0800 Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> wrote:
>
> > On 2/12/20 3:21 AM, David Hildenbrand wrote:
> > > On 11.02.20 06:24, Yang Shi wrote:
> > > > When kstrndup fails (returns NULL) there is no memory is allocated by
> > > > kmalloc, so no need to call kfree().
> > > "When kstrndup fails, no memory was allocated and we can exit directly."
> > Thanks for correcting the commit log.
> >
> > Andrew, do you prefer I send an updated version or you would just update
> > the patch in -mm tree?
> I have already done this.

Thanks!

> From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
> Subject: mm: vmpressure: don't need call kfree if kstrndup fails
>
> When kstrndup fails, no memory was allocated and we can exit directly.
>
> [david@xxxxxxxxxx: reword changelog]
> Link: http://lkml.kernel.org/r/1581398649-125989-1-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx
> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
>
>   mm/vmpressure.c |    6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
>
> --- a/mm/vmpressure.c~mm-vmpressure-dont-need-call-kfree-if-kstrndup-fails
> +++ a/mm/vmpressure.c
> @@ -371,10 +371,8 @@ int vmpressure_register_event(struct mem
>   	int ret = 0;
>   
>   	spec_orig = spec = kstrndup(args, MAX_VMPRESSURE_ARGS_LEN, GFP_KERNEL);
> -	if (!spec) {
> -		ret = -ENOMEM;
> -		goto out;
> -	}
> +	if (!spec)
> +		return -ENOMEM;
>   
>   	/* Find required level */
>   	token = strsep(&spec, ",");
> _