linux-kernel - Re: [PATCH] ndtest: Remove redundant NULL check

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Date:   Mon, 22 Mar 2021 13:20:29 -0700
From:   Ira Weiny <ira.weiny@...el.com>
To:     Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>
Cc:     dan.j.williams@...el.com, vishal.l.verma@...el.com,
        dave.jiang@...el.com, linux-nvdimm@...ts.01.org,
        linux-kernel@...r.kernel.org, Santosh Sivaraj <santosh@...six.org>
Subject: Re: [PATCH] ndtest: Remove redundant NULL check

On Mon, Mar 22, 2021 at 06:00:40PM +0800, Jiapeng Chong wrote:
> Fix the following coccicheck warnings:
> 
> ./tools/testing/nvdimm/test/ndtest.c:491:2-7: WARNING: NULL check before
> some freeing functions is not needed.

I don't think there is anything wrong with this patch specifically but why is
buf not checked for null after the vmalloc?

It seems to me that if size >= DIMM_SIZE and the vmalloc fails the gen pool
allocation is going to be leaked.

Ira

> 
> Reported-by: Abaci Robot <abaci@...ux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>
> ---
>  tools/testing/nvdimm/test/ndtest.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/tools/testing/nvdimm/test/ndtest.c b/tools/testing/nvdimm/test/ndtest.c
> index 6862915..98b4a43 100644
> --- a/tools/testing/nvdimm/test/ndtest.c
> +++ b/tools/testing/nvdimm/test/ndtest.c
> @@ -487,8 +487,7 @@ static void *ndtest_alloc_resource(struct ndtest_priv *p, size_t size,
>  buf_err:
>  	if (__dma && size >= DIMM_SIZE)
>  		gen_pool_free(ndtest_pool, __dma, size);
> -	if (buf)
> -		vfree(buf);
> +	vfree(buf);
>  	kfree(res);
>  
>  	return NULL;
> -- 
> 1.8.3.1
>