Re: [PATCH iproute2 v3 2/2] ip: ipstats: Do not hide HW statistics when hw_stats_info is missing

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 10 Sep 2026 11:20:57 +0200
Alexander Zubkov <green@qrator.net> wrote:

> ipstats_show_hw_stats() returns as soon as IFLA_OFFLOAD_XSTATS_HW_S_INFO
> is absent, dropping the counters that the message does carry.
> __ipstats_show_hw_stats() already copes with a NULL info attribute, so
> let it, and skip the record only when neither attribute is present.
> 
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Alexander Zubkov <green@qrator.net>
> ---

Ok to check for bugs, but this is not that much of a problem.

After patch 1 this is unreachable with a sane kernel.
rtnl_offload_xstats_fill() emits HW_S_INFO unconditionally whenever
its filter bit is set, and ipstats packs that bit together with
L3_STATS. The only way to get L3_STATS without HW_S_INFO is the
resumed message with prividx at L3_STATS, which patch 1 now merges.
GET is not NLM_F_MULTI so it cannot split, the monitor notification
carries HW_S_INFO only, and both attributes landed in the same kernel
series, so there is no version skew either.

The commit message still describes the v1 symptom. It is not dropping
any counters once patch 1 is in. If you want to keep it, reword it as
a consistency cleanup: __ipstats_show_hw_stats() already tolerates a
NULL at_hwsi, the wrapper does not. Otherwise drop it. Not going to
add a validator higher up for a message the kernel never sends.