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From: Dan Carpenter <dan.carpenter@oracle.com>
To: zhanglin <zhang.lin16@zte.com.cn>
Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net,
	jakub.kicinski@netronome.com, hawk@kernel.org,
	john.fastabend@gmail.com, mkubecek@suse.cz, jiri@mellanox.com,
	pablo@netfilter.org, f.fainelli@gmail.com,
	maxime.chevallier@bootlin.com, lirongqing@baidu.com,
	vivien.didelot@gmail.com, linyunsheng@huawei.com,
	natechancellor@gmail.com, arnd@arndb.de, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	xue.zhihong@zte.com.cn, wang.yi59@zte.com.cn,
	jiang.xuexin@zte.com.cn
Subject: Re: [PATCH] net: Zeroing the structure ethtool_wolinfo in ethtool_get_wol()
Date: Sat, 26 Oct 2019 17:24:58 +0300	[thread overview]
Message-ID: <20191026142458.GJ23523@kadam> (raw)
In-Reply-To: <1572076456-12463-1-git-send-email-zhang.lin16@zte.com.cn>

On Sat, Oct 26, 2019 at 03:54:16PM +0800, zhanglin wrote:
> memset() the structure ethtool_wolinfo that has padded bytes
> but the padded bytes have not been zeroed out.
> 
> Signed-off-by: zhanglin <zhang.lin16@zte.com.cn>
> ---
>  net/core/ethtool.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/core/ethtool.c b/net/core/ethtool.c
> index aeabc48..563a845 100644
> --- a/net/core/ethtool.c
> +++ b/net/core/ethtool.c
> @@ -1471,11 +1471,13 @@ static int ethtool_reset(struct net_device *dev, char __user *useraddr)
>  
>  static int ethtool_get_wol(struct net_device *dev, char __user *useraddr)
>  {
> -	struct ethtool_wolinfo wol = { .cmd = ETHTOOL_GWOL };
> +	struct ethtool_wolinfo wol;
>  

How did you detect that they weren't initialized?  Is this a KASAN
thing?

Most of the time GCC will zero out the padding bytes when you have an
initializer like this, but sometimes it just makes the intialization a
series of assignments which leaves the holes uninitialized.  I wish I
knew the rules so that I could check for it in Smatch.  Or even better,
I wish that there were an option to always zero the holes in this
situation...

regards,
dan carpenter


  reply	other threads:[~2019-10-26 14:26 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-26  7:54 [PATCH] net: Zeroing the structure ethtool_wolinfo in ethtool_get_wol() zhanglin
2019-10-26 14:24 ` Dan Carpenter [this message]
2019-10-26 15:52   ` Joe Perches
2019-10-26 18:21 ` David Miller
2019-10-26 19:40 ` Joe Perches
2019-10-26 20:17   ` [Cocci] " Julia Lawall
2019-11-21 10:23   ` Enrico Weigelt, metux IT consult
2019-11-21 11:19     ` Michal Kubecek
2019-11-21 11:58       ` Julia Lawall
2019-11-21 12:07       ` Dan Carpenter
2019-11-21 13:38         ` Michal Kubecek
2019-11-21 20:40           ` Julia Lawall

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