From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CB8BC282CE for ; Tue, 4 Jun 2019 21:24:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B91C207E0 for ; Tue, 4 Jun 2019 21:24:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726477AbfFDVYi (ORCPT ); Tue, 4 Jun 2019 17:24:38 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:52596 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726179AbfFDVYi (ORCPT ); Tue, 4 Jun 2019 17:24:38 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 9A9201500FF35; Tue, 4 Jun 2019 14:24:37 -0700 (PDT) Date: Tue, 04 Jun 2019 14:24:36 -0700 (PDT) Message-Id: <20190604.142436.1951250822599766015.davem@davemloft.net> To: fw@strlen.de Cc: netdev@vger.kernel.org, syzbot+bad6e32808a3a97b1515@syzkaller.appspotmail.com Subject: Re: [PATCH net-next] net: ipv4: fix rcu lockdep splat due to wrong annotation From: David Miller In-Reply-To: <20190603204144.28320-1-fw@strlen.de> References: <000000000000bec591058a6fd889@google.com> <20190603204144.28320-1-fw@strlen.de> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 04 Jun 2019 14:24:37 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Florian Westphal Date: Mon, 3 Jun 2019 22:41:44 +0200 > syzbot triggered following splat when strict netlink > validation is enabled: > > net/ipv4/devinet.c:1766 suspicious rcu_dereference_check() usage! > > This occurs because we hold RTNL mutex, but no rcu read lock. > The second call site holds both, so just switch to the _rtnl variant. > > Reported-by: syzbot+bad6e32808a3a97b1515@syzkaller.appspotmail.com > Fixes: 2638eb8b50cf ("net: ipv4: provide __rcu annotation for ifa_list") > Signed-off-by: Florian Westphal Applied.