Re: [PATCH net] psample: zero the netlink attribute padding in PSAMPLE_ATTR_DATA

[Jakub Kicinski <kuba@kernel.org>]

On Sat, 13 Jun 2026 16:33:44 -0700 Xiang Mei wrote:
> That looks better. I just found that nla_reserve can memset for us:
> 
> diff --git a/net/psample/psample.c b/net/psample/psample.c
> index 7763662036fb..c112e1f0ccac 100644
> --- a/net/psample/psample.c
> +++ b/net/psample/psample.c
> @@ -476,12 +476,11 @@ void psample_sample_packet(struct psample_group *group,
>  		goto error;
> 
>  	if (data_len) {
> -		int nla_len = nla_total_size(data_len);
>  		struct nlattr *nla;
> 
> -		nla = skb_put(nl_skb, nla_len);
> -		nla->nla_type = PSAMPLE_ATTR_DATA;
> -		nla->nla_len = nla_attr_size(data_len);
> +		nla = nla_reserve(nl_skb, PSAMPLE_ATTR_DATA, data_len);
> +		if (!nla)
> +			goto error;
> 
>  		if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
>  			goto error;
> 
> Let me know if the new patch makes sense.

I assumed the author intentionally was avoiding the memset for 
the memory we will override with data. Otherwise the whole dance 
could be avoided and nla_put() would have been the answer.