netdev - [PATCH net-next v2 4/7] net: openvswitch: fix load tearing with u64

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Message-ID: <20260123162159.2877941-5-mmyangfl@gmail.com>
Date: Sat, 24 Jan 2026 00:21:36 +0800
From: David Yang <mmyangfl@...il.com>
To: netdev@...r.kernel.org
Cc: David Yang <mmyangfl@...il.com>,
	Aaron Conole <aconole@...hat.com>,
	Eelco Chaudron <echaudro@...hat.com>,
	Ilya Maximets <i.maximets@....org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	dev@...nvswitch.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH net-next v2 4/7] net: openvswitch: fix load tearing with u64_stats

On 64bit arches, struct u64_stats_sync is empty and provides no help
against load/store tearing. struct copying should not be considered
tear-free. Use u64_stats_reads() instead.

Signed-off-by: David Yang <mmyangfl@...il.com>
---
 net/openvswitch/datapath.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index d5b6e2002bc1..8ba94df7f942 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -770,7 +770,8 @@ static void get_dp_stats(const struct datapath *dp, struct ovs_dp_stats *stats,
 
 		do {
 			start = u64_stats_fetch_begin(&percpu_stats->syncp);
-			local_stats = *percpu_stats;
+			u64_stats_reads(&local_stats, percpu_stats,
+					sizeof(local_stats));
 		} while (u64_stats_fetch_retry(&percpu_stats->syncp, start));
 
 		stats->n_hit += local_stats.n_hit;
-- 
2.51.0