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Date:   Tue, 12 Jun 2018 14:55:25 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Zhouyang Jia <jiazhouyang09@gmail.com>
Cc:     devel@driverdev.osuosl.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: gdm724x: add error handling for nlmsg_put
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On Mon, Jun 11, 2018 at 01:09:24PM +0800, Zhouyang Jia wrote:
> When nlmsg_put fails, the lack of error-handling code may
> cause unexpected results.
> 
> This patch adds error-handling code after calling nlmsg_put.
> 
> Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> ---
>  drivers/staging/gdm724x/netlink_k.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/staging/gdm724x/netlink_k.c b/drivers/staging/gdm724x/netlink_k.c
> index abe2425..4623140 100644
> --- a/drivers/staging/gdm724x/netlink_k.c
> +++ b/drivers/staging/gdm724x/netlink_k.c
> @@ -119,6 +119,9 @@ int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
>  	seq++;
>  
>  	nlh = nlmsg_put(skb, 0, seq, type, len, 0);
> +	if (!nlh)
> +		return -EMSGSIZE;

This can't fail.  We just allocated skb on the line before and we
allocated enough space for "len".  Also if we *did* hit a bug here then
we would need to do some more cleanup instead of a direct return.

regards,
dan carpenter