From patchwork Thu May 14 07:02:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Madhuparna Bhowmik X-Patchwork-Id: 1289950 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=UiSjcqLv; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49N2Xy4WrYz9sV8 for ; Thu, 14 May 2020 17:02:26 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725967AbgENHCY (ORCPT ); Thu, 14 May 2020 03:02:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725838AbgENHCX (ORCPT ); Thu, 14 May 2020 03:02:23 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65EC0C061A0C; Thu, 14 May 2020 00:02:22 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id s20so821693plp.6; Thu, 14 May 2020 00:02:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=exf19t930SX+cfRNGe3IOO9qF0esqQVEBJnT+ceqQ/8=; b=UiSjcqLv1eEZMcvmQdBlNM5ZyA8GwZxaoMw9FDpacqki9xA2V/XiBs03oWn0+JpTvr U2lS4lW8M7veY9L3habkuCeBuEk2nK3kwVsZ2K5f/NAIS7dErrdJg12dVvgXn4tX/Run s2j2m4+t1Rh54mWaYSuiNGIeC11p/VWoJMHkXVOvCT5haLvCbopVP8BhFhduvokHT8pS bTTJq2j8+5IE4NkpAd+8+g8dbxcTr02nwfVX4BhJb+cmJfx6lu3KcA74lvOAZuKO3pOh k5zmgkmUMvINjGYMgwgk5wI5U+0MLBBbXTz/B9oMoucy6h6nFOdB5VgIU6fF/vzGejOP qnjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=exf19t930SX+cfRNGe3IOO9qF0esqQVEBJnT+ceqQ/8=; b=ZDqb0XzS+H7jHLGw8muXs7x5+MkmxDvBnVSGXW/ygtl4MASFJe6DImsbskANYw7n9V lGLENLlVq8cdQSvuLp0FLhO436pW/sy9xnodB+4QMXhbOU/STgKBQ35UzZkU95FbslX5 NYyjhbUqxo51GPIKCX4cWsNTPvR0rBCmbxaUeKXy7igRKizPNZF+ZMKe8/2nsjXO+6I1 rZ7yeoNet4FKk1B0jqdMPgZWg3WVW5HERmboA9wngoWywUR4zjLELgLH4CMZ44dwFT0C mH6paAEKy/d5Koy//rL+M0Bheqgm91VJeDwJQ12OY0EE9KvLmNjfTu4Sfsq+KKBs3jRI XDag== X-Gm-Message-State: AOAM5325qP4kW7BVA3P0/xUxCAhVFPzmjBpXz2Qx31xa7+xyMr7hjZbw 8nFt2k5hT2+Q6BlNVIZplg== X-Google-Smtp-Source: ABdhPJxCYR2LmEz5QYdvaLfhTkPuGVvRQAIsEbKTvtGgBIEY6YC9lI6Y4UDTOB9L9yVvyTO172nIAQ== X-Received: by 2002:a17:902:8c8f:: with SMTP id t15mr2735774plo.183.1589439741756; Thu, 14 May 2020 00:02:21 -0700 (PDT) Received: from localhost.localdomain ([2409:4071:5b5:d53:89fb:f860:f992:54ab]) by smtp.gmail.com with ESMTPSA id i128sm1446807pfc.149.2020.05.14.00.02.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 May 2020 00:02:20 -0700 (PDT) From: madhuparnabhowmik10@gmail.com To: davem@davemloft.net, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, kuba@kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, sfr@canb.auug.org.au, frextrite@gmail.com, joel@joelfernandes.org, paulmck@kernel.org, cai@lca.pw, Madhuparna Bhowmik Subject: [PATCH net] ipv6: Fix suspicious RCU usage warning in ip6mr Date: Thu, 14 May 2020 12:32:04 +0530 Message-Id: <20200514070204.3108-1-madhuparnabhowmik10@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Madhuparna Bhowmik This patch fixes the following warning: ============================= WARNING: suspicious RCU usage 5.7.0-rc4-next-20200507-syzkaller #0 Not tainted ----------------------------- net/ipv6/ip6mr.c:124 RCU-list traversed in non-reader section!! ipmr_new_table() returns an existing table, but there is no table at init. Therefore the condition: either holding rtnl or the list is empty is used. Fixes: d13fee049f ("Default enable RCU list lockdep debugging with .."): WARNING: suspicious RCU usage Reported-by: kernel test robot Suggested-by: Jakub Kicinski Signed-off-by: Madhuparna Bhowmik --- net/ipv6/ip6mr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 65a54d74acc1..fbe282bb8036 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -98,7 +98,7 @@ static void ipmr_expire_process(struct timer_list *t); #ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES #define ip6mr_for_each_table(mrt, net) \ list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list, \ - lockdep_rtnl_is_held()) + lockdep_rtnl_is_held() || list_empty(&net->ipv6.mr6_tables)) static struct mr_table *ip6mr_mr_table_iter(struct net *net, struct mr_table *mrt)