linux-kernel - Re: ALSA: compress: Memset timestamp structure to zero.

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Date:   Tue, 23 Aug 2016 15:45:38 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     "Luis Henriques" <luis.henriques@...onical.com>
Cc:     "Krishnankutty Kolathappilly" <kkolat@...eaurora.org>,
        <alsa-devel@...a-project.org>, "Vinod Koul" <vinod.koul@...el.com>,
        "Jaroslav Kysela" <perex@...ex.cz>, <linux-kernel@...r.kernel.org>
Subject: Re: ALSA: compress: Memset timestamp structure to zero.

On Tue, 23 Aug 2016 15:40:37 +0200,
Luis Henriques wrote:
> 
> From: Krishnankutty Kolathappilly <kkolat@...eaurora.org>
> 
> snd_compr_tstamp is initialized using aggregate initialization
> that does not zero out the padded bytes. Initialize timestamp
> structure to zero using memset to avoid this.
> 
> CRs-Fixed: 568717
> Change-Id: I7a7d188705161f06201f1a1f2945bb6acd633d5d
> Signed-off-by: Krishnankutty Kolathappilly <kkolat@...eaurora.org>

Vinod already informed me about this, and we agreed that it doesn't
make any sense.  What does it really fix?


thanks,

Takashi

> ---
>  sound/core/compress_offload.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
> index 2c498488af6c..84aaa07ca853 100644
> --- a/sound/core/compress_offload.c
> +++ b/sound/core/compress_offload.c
> @@ -659,9 +659,10 @@ snd_compr_set_metadata(struct snd_compr_stream *stream, unsigned long arg)
>  static inline int
>  snd_compr_tstamp(struct snd_compr_stream *stream, unsigned long arg)
>  {
> -	struct snd_compr_tstamp tstamp = {0};
> +	struct snd_compr_tstamp tstamp;
>  	int ret;
>  
> +	memset(&tstamp, 0, sizeof(tstamp));
>  	ret = snd_compr_update_tstamp(stream, &tstamp);
>  	if (ret == 0)
>  		ret = copy_to_user((struct snd_compr_tstamp __user *)arg,
>