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

[Alexander Zubkov <green@qrator.net>]

ipstats_show_hw_stats() returns as soon as the
IFLA_OFFLOAD_XSTATS_HW_S_INFO attribute is absent, silently 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.

There is no known way to reach this through "ip stats": the l3_stats
descriptor always requests HW_S_INFO next to the counters, and since the
previous patch the two are reassembled even when the kernel splits them
across messages. This is a hardening measure so that a message carrying
just the counters is displayed rather than silently discarded.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Alexander Zubkov <green@qrator.net>
---
 ip/ipstats.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ip/ipstats.c b/ip/ipstats.c
index c531885f..54b8267d 100644
--- a/ip/ipstats.c
+++ b/ip/ipstats.c
@@ -472,13 +472,16 @@ static int ipstats_show_hw_stats(struct ipstats_stat_show_attrs *attrs,
 	int err = 0;
 
 	at_hwsi = ipstats_stat_show_get_attr(attrs, group, hw_s_info, &err);
-	if (at_hwsi == NULL)
+	if (at_hwsi == NULL && err != 0)
 		return err;
 
 	at_stats = ipstats_stat_show_get_attr(attrs, group, hw_stats, &err);
 	if (at_stats == NULL && err != 0)
 		return err;
 
+	if (at_hwsi == NULL && at_stats == NULL)
+		return 0;
+
 	return __ipstats_show_hw_stats(at_hwsi, at_stats, idx);
 }
 
-- 
2.55.0