From ccbb3c6c065beddb860e94a318c950fa9bbfdb2a Mon Sep 17 00:00:00 2001
From: Andrew Gallagher <andrewjcg@meta.com>
Date: Wed, 18 Dec 2024 07:40:37 -0800
Subject: [PATCH] Fix `-Wgnu-variable-sized-type-not-at-end` errors across
 fbcode

Summary:
Newer versions of the kernel have moved to flexible array members,
which triggers compiler warnings with the pattern used here.

https://patchwork.kernel.org/project/linux-nvdimm/patch/20220627180432.GA136081@embeddedor/

Reviewed By: psaab

Differential Revision: D67374150
---
 dynolog/src/rdmamon/EthtoolCounters.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/dynolog/src/rdmamon/EthtoolCounters.h b/dynolog/src/rdmamon/EthtoolCounters.h
index 0da238a..3ae9ed0 100644
--- a/dynolog/src/rdmamon/EthtoolCounters.h
+++ b/dynolog/src/rdmamon/EthtoolCounters.h
@@ -61,9 +61,11 @@ class EthtoolCounters {
 
   [[nodiscard]] bool setup_ethtool_counters(
       const std::vector<std::string>& eth_counter_names_) {
-    struct {
+    union {
       struct ethtool_sset_info hdr;
-      uint32_t buf[1];
+      // Allocate extra space for flexible array member.
+      uint8_t
+          _buf[offsetof(struct ethtool_sset_info, data) + sizeof(uint32_t[1])];
     } ss_stats;
     uint32_t ss_stats_len;