linux-kernel - Re: [V2] kexec_file: use crypto_free_shash to free memory

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Message-ID: <20170810022834.GA2345@x1>
Date:   Thu, 10 Aug 2017 10:28:34 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Pan Bian <bianpan2016@....com>, akpm@...ux-foundation.org
Cc:     Eric Biederman <ebiederm@...ssion.com>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [V2] kexec_file: use crypto_free_shash to free memory

On 08/09/17 at 07:30pm, Pan Bian wrote:
> In function kexec_calculate_store_digests(), kfree() is used to free
> memory allocated by crypto_alloc_shash(). It is better to use function
> crypto_free_shash(), which frees up tfm and any resources associated with
> it. And then, the refcount of the algorithm used in crypto_alloc_shash()
> is also dropped.
> 
> Signed-off-by: Pan Bian <bianpan2016@....com>

Makes sense to call the crypto alloc/free api in pairs.

Acked-by: Baoquan He <bhe@...hat.com>

> ---
>  kernel/kexec_file.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 9f48f44..94eeb38 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -627,7 +627,7 @@ static int kexec_calculate_store_digests(struct kimage *image)
>  out_free_desc:
>  	kfree(desc);
>  out_free_tfm:
> -	kfree(tfm);
> +	crypto_free_shash(tfm);
>  out:
>  	return ret;
>  }
> -- 
> 1.9.1
> 
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

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