From patchwork Wed Feb 2 11:01:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 12732814 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34C76C433EF for ; Wed, 2 Feb 2022 11:01:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343628AbiBBLBu (ORCPT ); Wed, 2 Feb 2022 06:01:50 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:56864 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343621AbiBBLBs (ORCPT ); Wed, 2 Feb 2022 06:01:48 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1C41761652 for ; Wed, 2 Feb 2022 11:01:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D33C6C004E1; Wed, 2 Feb 2022 11:01:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643799707; bh=KZY92ogNcgCGz2j9fi7V1cmGq9PcGbFsjtfUKccxt48=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lNxWjXU5H8btlpm3mMl1sT/OSnn49nX5s9OgiqU6nv5zmf/m1aN4tBAc7A9WKGJ+S 0qZ9IA7zkoMdgqOWckmoFWemF/ZIGpFEMPMLfCuLXrj9JgQLvldkMi/OaRa2ctgeHF Z7KcemsKlGmagIZlfulirhjWrqLuB0h3ReIEhmKMw62VsEVmFzbeF+7kUZgfm6YLa4 a8F01bXFV8w58gnZcdzzv67EJ8kSmkYK1Hmce5keXNjNPqJsfh2l+5fE/Iqth4SVvL ShVGmvEVhRB6wIvhz0P0DZrcmHukSIduHiaZQL7MA+Lna8QYhXjHZFn+l0zT8KCiIH 8kuGYeceRH+3Q== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org Cc: Antoine Tenart , netdev@vger.kernel.org, vladbu@nvidia.com, pabeni@redhat.com, pshelar@ovn.org Subject: [PATCH net 2/2] net: fix a memleak when uncloning an skb dst and its metadata Date: Wed, 2 Feb 2022 12:01:37 +0100 Message-Id: <20220202110137.470850-3-atenart@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220202110137.470850-1-atenart@kernel.org> References: <20220202110137.470850-1-atenart@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When uncloning an skb dst and its associated metadata, a new dst+metadata is allocated and later replaces the old one in the skb. This is helpful to have a non-shared dst+metadata attached to a specific skb. The issue is the uncloned dst+metadata is initialized with a refcount of 1, which is increased to 2 before attaching it to the skb. When tun_dst_unclone returns, the dst+metadata is only referenced from a single place (the skb) while its refcount is 2. Its refcount will never drop to 0 (when the skb is consumed), leading to a memory leak. Fix this by removing the call to dst_hold in tun_dst_unclone, as the dst+metadata refcount is already 1. Fixes: fc4099f17240 ("openvswitch: Fix egress tunnel info.") Cc: Pravin B Shelar Reported-by: Vlad Buslov Tested-by: Vlad Buslov Signed-off-by: Antoine Tenart --- include/net/dst_metadata.h | 1 - 1 file changed, 1 deletion(-) diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h index c8f8b7b56bba..edd75c89222d 100644 --- a/include/net/dst_metadata.h +++ b/include/net/dst_metadata.h @@ -135,7 +135,6 @@ static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb) #endif skb_dst_drop(skb); - dst_hold(&new_md->dst); skb_dst_set(skb, &new_md->dst); return new_md; }