From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 09D0141D20E for ; Thu, 23 Jul 2026 14:42:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784817781; cv=none; b=nWupx0kXFSHDsab0N9CsAR7LV91Gj9dnwBwtipgNwPpDUCwuIswNNGkrs2uEyx5F1Jy3koWCJkHVMtr1SbQrOreZdsnTnZabEfQCCWr8ipTzCD9XcNKHTT1aOOidYNrIiQwOypV0AVK315NNmnYekSAXf7KqIYCpBDkGoJ9TQf4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784817781; c=relaxed/simple; bh=SaGT5/k0Hq7us1Xh96BcYHTQxGZSs402OfH8hNSQErY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=idGrNBi9F/x1RleJQFh2c+3lLafkMjW7uhAjwWb8nJAaZMw/ASY2UNMZKFNGjhCZ1ErAu+rF2rsZV9Lns/bV93CiuldE0sgaSiFqYDN764EastwjPUSG3BtHpGU6No00mNmZBitJzMI/D4/McsiAjOmk2Oqmyw/Hw2NCKBFn+5w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=GjkyRkmd; arc=none smtp.client-ip=209.85.222.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="GjkyRkmd" Received: by mail-qk1-f200.google.com with SMTP id af79cd13be357-93106d8af18so105298185a.0 for ; Thu, 23 Jul 2026 07:42:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1784817776; x=1785422576; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=7G6+WmalGeshMr5rrbPWKhucx6Kb/G0FkKHu8ELLz48=; b=GjkyRkmdjlx0WuRJ2NpsCYJypkU2QOcewKBHWz+aVDgWwHBDc8G0WeQP+SW9NOUVvH cx+0hlT788gmTvuGLgxRhMHekJjEH9/qL8sx/1JJsT1DOsoH7Sp5lQtrOZD3c0mBzvk0 3iL5xnStIVLUTQRRb+TEIeISfNXUKZw4td1a5Tbj5hdJqO/iuJ17946sdv5OPiFxmM2c HXGk1mJin1J0Vktxk+kOZ8iJSalWrTGaffpuwEb8fTYKNaagcU7mh0q63zeQqz0YyL5q oUg4i1n74/+NEG15gzbX9gLaRhziqFBjJpQSCJozdXxsQZDWBakbjvNULLDBFBHdsSwt wI+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784817776; x=1785422576; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=7G6+WmalGeshMr5rrbPWKhucx6Kb/G0FkKHu8ELLz48=; b=ATBlvNVZCIRuiLjDqxDXWo1F5JIZDLOZw9yiP9wMQHMjM0Nqere+8A+oqMt/NcKHaz e3aoisN+9J2+7Ua6pZ/fO3eREiMSSYkHJ1GDnO3arWi03wS+A7ttgjffGFUVvPIb5bVF iOsgF6d+IhTEWDAzei+k6EAtFsf4K/3QcaWzU/qMWaOCFqcZRJkd2hspgTCM1zygsfqj Y9FYAeXGaiZwILvaDiEFzUA6U8tePV9PW04hsPaKfkydU88dZEsKGmxQq5IYDk/Vc7iJ SnlnnMchdSNM11a3DEuLC6b4pT+Kz+DnYOXX7uknsxxANEp+Cevqci2aWOWP+KypbrDD lZwQ== X-Forwarded-Encrypted: i=1; AHgh+RoFcGtwr4J8+gQ8j9lFaD4A2Jilrk23JhxhJP73ChvkF5mvK2JZsH5xMgVCJEXo3Ttx+drSxhg=@vger.kernel.org X-Gm-Message-State: AOJu0YwqLkQHAs34QByuTdo7RIo72txEiyA/A7IX+pdRT/sLdP6WmlY8 N/Aqh3Kuq07HWSJUspYTUo8KeSALOwXPauYGn4ofEEYjoJlhcLeiTFq4WtMZelVprBooMaz5d/h EIPBIp1ZC3DhXxQ== X-Received: from qkww19.prod.google.com ([2002:a05:620a:953:b0:92e:e46b:a01b]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:480b:b0:930:f9a6:11ac with SMTP id af79cd13be357-93103a59d1dmr315209785a.71.1784817775196; Thu, 23 Jul 2026 07:42:55 -0700 (PDT) Date: Thu, 23 Jul 2026 14:42:47 +0000 In-Reply-To: <20260723144249.759100-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260723144249.759100-1-edumazet@google.com> X-Mailer: git-send-email 2.55.0.229.g6434b31f56-goog Message-ID: <20260723144249.759100-4-edumazet@google.com> Subject: [PATCH net 3/5] vxlan: use neigh_ha_snapshot() in route_shortcircuit() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Ido Schimmel , Andrew Lunn , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" The neighbour hardware address n->ha can be updated asynchronously by the neighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without holding the seqlock loop can lead to torn reads or reading a partially updated MAC address. Use neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under read_seqbegin()/read_seqretry() lock protection before using it. Note that arp_reduce() and neigh_reduce() seem to have the same issue left for future patches. Fixes: e4f67addf158 ("add DOVE extensions for VXLAN") Cc: stable@vger.kernel.org Signed-off-by: Eric Dumazet --- drivers/net/vxlan/vxlan_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index fb4a706cd5786d1937b1922acced31ffdb187c2f..10dd19eec09e266197ee51330a652f4e76c9643a 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -2159,9 +2159,11 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb) } if (n) { + u8 haddr[ETH_ALEN]; bool diff; - diff = !ether_addr_equal(eth_hdr(skb)->h_dest, n->ha); + neigh_ha_snapshot(haddr, n, dev); + diff = !ether_addr_equal_unaligned(eth_hdr(skb)->h_dest, haddr); if (diff) { if (skb_cow_head(skb, 0)) { neigh_release(n); @@ -2169,7 +2171,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb) } memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, dev->addr_len); - memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len); + memcpy(eth_hdr(skb)->h_dest, haddr, dev->addr_len); } neigh_release(n); return diff; -- 2.55.0.229.g6434b31f56-goog