From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52E6E37104C; Tue, 17 Feb 2026 16:33:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771345997; cv=none; b=C8gdM29tBpK+Fqn/+Cix+gYd+0O4yc82o5QCvxGQ5hY84Xmz7SuPlhFLv2fXEb+AS8LEJk9GvdqfuL9zENqmuMLkl3W2FTru61WL5Z475y6oQHtfH1ubJPIHrQbONPqQQ/0fa26UHu8BZs5sBIPD/tSndi/8nnyL0bIDqFuLo7Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771345997; c=relaxed/simple; bh=FmEL3yz60Zh7FKnuB3qprdNhLNsoiToC9zai7XaVdDc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VX+X1YdEB+g6a3zdWNnX0FQGxOVIdl7DvrJXRXX4es3OPlAPczeygLohlCKTuF1uD5WgfdWF9XNgUUk+eozMuNcFfKrku4raNltNtL3KFki9Gb7Sbsuub9R8XzYUoXrwASddB6rIFZ4/Sp5AyMucdK+0Qs7Tq7qFOQBmDu3tegk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id D194A60CF7; Tue, 17 Feb 2026 17:33:14 +0100 (CET) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH net 08/10] ipvs: do not keep dest_dst if dev is going down Date: Tue, 17 Feb 2026 17:32:31 +0100 Message-ID: <20260217163233.31455-9-fw@strlen.de> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260217163233.31455-1-fw@strlen.de> References: <20260217163233.31455-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Julian Anastasov There is race between the netdev notifier ip_vs_dst_event() and the code that caches dst with dev that is going down. As the FIB can be notified for the closed device after our handler finishes, it is possible valid route to be returned and cached resuling in a leaked dev reference until the dest is not removed. To prevent new dest_dst to be attached to dest just after the handler dropped the old one, add a netif_running() check to make sure the notifier handler is not currently running for device that is closing. Fixes: 7a4f0761fce3 ("IPVS: init and cleanup restructuring") Signed-off-by: Julian Anastasov Signed-off-by: Florian Westphal --- net/netfilter/ipvs/ip_vs_xmit.c | 46 ++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c index f861d116cc33..4389bfe3050d 100644 --- a/net/netfilter/ipvs/ip_vs_xmit.c +++ b/net/netfilter/ipvs/ip_vs_xmit.c @@ -294,6 +294,12 @@ static inline bool decrement_ttl(struct netns_ipvs *ipvs, return true; } +/* rt has device that is down */ +static bool rt_dev_is_down(const struct net_device *dev) +{ + return dev && !netif_running(dev); +} + /* Get route to destination or remote server */ static int __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb, @@ -309,9 +315,11 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb, if (dest) { dest_dst = __ip_vs_dst_check(dest); - if (likely(dest_dst)) + if (likely(dest_dst)) { rt = dst_rtable(dest_dst->dst_cache); - else { + if (ret_saddr) + *ret_saddr = dest_dst->dst_saddr.ip; + } else { dest_dst = ip_vs_dest_dst_alloc(); spin_lock_bh(&dest->dst_lock); if (!dest_dst) { @@ -327,14 +335,22 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb, ip_vs_dest_dst_free(dest_dst); goto err_unreach; } - __ip_vs_dst_set(dest, dest_dst, &rt->dst, 0); + /* It is forbidden to attach dest->dest_dst if + * device is going down. + */ + if (!rt_dev_is_down(dst_dev_rcu(&rt->dst))) + __ip_vs_dst_set(dest, dest_dst, &rt->dst, 0); + else + noref = 0; spin_unlock_bh(&dest->dst_lock); IP_VS_DBG(10, "new dst %pI4, src %pI4, refcnt=%d\n", &dest->addr.ip, &dest_dst->dst_saddr.ip, rcuref_read(&rt->dst.__rcuref)); + if (ret_saddr) + *ret_saddr = dest_dst->dst_saddr.ip; + if (!noref) + ip_vs_dest_dst_free(dest_dst); } - if (ret_saddr) - *ret_saddr = dest_dst->dst_saddr.ip; } else { noref = 0; @@ -471,9 +487,11 @@ __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb, if (dest) { dest_dst = __ip_vs_dst_check(dest); - if (likely(dest_dst)) + if (likely(dest_dst)) { rt = dst_rt6_info(dest_dst->dst_cache); - else { + if (ret_saddr) + *ret_saddr = dest_dst->dst_saddr.in6; + } else { u32 cookie; dest_dst = ip_vs_dest_dst_alloc(); @@ -494,14 +512,22 @@ __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb, } rt = dst_rt6_info(dst); cookie = rt6_get_cookie(rt); - __ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie); + /* It is forbidden to attach dest->dest_dst if + * device is going down. + */ + if (!rt_dev_is_down(dst_dev_rcu(&rt->dst))) + __ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie); + else + noref = 0; spin_unlock_bh(&dest->dst_lock); IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n", &dest->addr.in6, &dest_dst->dst_saddr.in6, rcuref_read(&rt->dst.__rcuref)); + if (ret_saddr) + *ret_saddr = dest_dst->dst_saddr.in6; + if (!noref) + ip_vs_dest_dst_free(dest_dst); } - if (ret_saddr) - *ret_saddr = dest_dst->dst_saddr.in6; } else { noref = 0; dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm, -- 2.52.0