net: bridge: mcast: fix memcpy with u64_stats

On 64bit arches, struct u64_stats_sync is empty and provides no help
against load/store tearing. memcpy() should not be considered atomic
against u64 values. Use u64_stats_copy() instead.

Signed-off-by: David Yang <mmyangfl@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260120092137.2161162-3-mmyangfl@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index d55a4ab87837f7eaa0247245816beb9bec3c02e5..dccae08b4f4c40c6849ca8310827036c82bb273e 100644 (file)
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -5201,7 +5201,7 @@ void br_multicast_get_stats(const struct net_bridge *br,
 
                do {
                        start = u64_stats_fetch_begin(&cpu_stats->syncp);
-                       memcpy(&temp, &cpu_stats->mstats, sizeof(temp));
+                       u64_stats_copy(&temp, &cpu_stats->mstats, sizeof(temp));
                } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
 
                mcast_stats_add_dir(tdst.igmp_v1queries, temp.igmp_v1queries);