Re: [PATCH iproute2-next v2 1/2] iplink: print warning for missing VF data

[David Ahern <dsahern@gmail.com>]

On 1/26/21 10:40 AM, Edwin Peer wrote:
> The kernel might truncate VF info in IFLA_VFINFO_LIST. Compare the
> expected number of VFs in IFLA_NUM_VF to how many were found in the
> list and warn accordingly.
> 
> Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
> ---
>  ip/ipaddress.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/ip/ipaddress.c b/ip/ipaddress.c
> index 571346b15cc3..0bbcee2b3bb2 100644
> --- a/ip/ipaddress.c
> +++ b/ip/ipaddress.c
> @@ -922,6 +922,7 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
>  	const char *name;
>  	unsigned int m_flag = 0;
>  	SPRINT_BUF(b1);
> +	bool truncated_vfs = false;
>  
>  	if (n->nlmsg_type != RTM_NEWLINK && n->nlmsg_type != RTM_DELLINK)
>  		return 0;
> @@ -1199,15 +1200,18 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
>  
>  	if ((do_link || show_details) && tb[IFLA_VFINFO_LIST] && tb[IFLA_NUM_VF]) {
>  		struct rtattr *i, *vflist = tb[IFLA_VFINFO_LIST];
> -		int rem = RTA_PAYLOAD(vflist);
> +		int rem = RTA_PAYLOAD(vflist), count = 0;
>  
>  		open_json_array(PRINT_JSON, "vfinfo_list");
>  		for (i = RTA_DATA(vflist); RTA_OK(i, rem); i = RTA_NEXT(i, rem)) {
>  			open_json_object(NULL);
>  			print_vfinfo(fp, ifi, i);
>  			close_json_object();
> +			count++;
>  		}
>  		close_json_array(PRINT_JSON, NULL);
> +		if (count != rta_getattr_u32(tb[IFLA_NUM_VF]))
> +			truncated_vfs = true;
>  	}
>  
>  	if (tb[IFLA_PROP_LIST]) {
> @@ -1228,6 +1232,9 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
>  
>  	print_string(PRINT_FP, NULL, "%s", "\n");
>  	fflush(fp);
> +	/* prettier here if stderr and stdout go to the same place */
> +	if (truncated_vfs)
> +		fprintf(stderr, "Truncated VF list: %s\n", name);
>  	return 1;
>  }
>  
> 

LGTM. I think it should go to the main branch versus -next.