From: Sven Eckelmann <sven@narfation.org>
Date: Sat, 13 Jun 2026 21:50:28 +0000 (+0200)
Subject: batman-adv: dat: prevent false sharing between VLANs
X-Git-Tag: v7.2-rc1~29^2~75^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=20d7658b74169f86d4ac01b9185b3eadddf71f28;p=thirdparty%2Flinux.git

batman-adv: dat: prevent false sharing between VLANs

The local hash of DAT entries is supposed to be VLAN (VID) aware. But
the adding to the hash and the search in the hash were not checking the VID
information of the hash entries. The entries would therefore only be
correctly separated when batadv_hash_dat() didn't select the same buckets
for different VIDs.

Cc: stable@kernel.org
Fixes: be1db4f6615b ("batman-adv: make the Distributed ARP Table vlan aware")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---

diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index aaea155b94038..ae39ceaa2e29a 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -215,10 +215,13 @@ static void batadv_dat_purge(struct work_struct *work)
  */
 static bool batadv_compare_dat(const struct hlist_node *node, const void *data2)
 {
-	const void *data1 = container_of(node, struct batadv_dat_entry,
-					 hash_entry);
+	const struct batadv_dat_entry *entry1;
+	const struct batadv_dat_entry *entry2;
 
-	return memcmp(data1, data2, sizeof(__be32)) == 0;
+	entry1 = container_of(node, struct batadv_dat_entry, hash_entry);
+	entry2 = data2;
+
+	return entry1->ip == entry2->ip && entry1->vid == entry2->vid;
 }
 
 /**
@@ -345,6 +348,9 @@ batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip,
 		if (dat_entry->ip != ip)
 			continue;
 
+		if (dat_entry->vid != vid)
+			continue;
+
 		if (!kref_get_unless_zero(&dat_entry->refcount))
 			continue;