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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 19C21C28CF6 for ; Wed, 1 Aug 2018 18:46:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB5A720840 for ; Wed, 1 Aug 2018 18:46:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB5A720840 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387406AbeHAUdr (ORCPT ); Wed, 1 Aug 2018 16:33:47 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:51200 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726116AbeHAUdr (ORCPT ); Wed, 1 Aug 2018 16:33:47 -0400 Received: from localhost (c-71-59-158-49.hsd1.or.comcast.net [71.59.158.49]) (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 DB452100A24BE; Wed, 1 Aug 2018 11:46:39 -0700 (PDT) Date: Wed, 01 Aug 2018 11:46:36 -0700 (PDT) Message-Id: <20180801.114636.279269263935333136.davem@davemloft.net> To: xiyou.wangcong@gmail.com Cc: sd@queasysnail.net, eric.dumazet@gmail.com, syzbot+41f9c04b50ef70c66947@syzkaller.appspotmail.com, christian.brauner@ubuntu.com, dsahern@gmail.com, fw@strlen.de, jbenc@redhat.com, ktkhai@virtuozzo.com, linux-kernel@vger.kernel.org, lucien.xin@gmail.com, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: KASAN: use-after-free Read in rtnetlink_put_metrics From: David Miller In-Reply-To: References: <20180731134014.GA32114@bistromath.localdomain> X-Mailer: Mew version 6.7 on Emacs 26 / Mule 6.0 (HANACHIRUSATO) 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]); Wed, 01 Aug 2018 11:46:40 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cong Wang Date: Tue, 31 Jul 2018 16:03:13 -0700 > Looks like this commit is completely unnecessary, > fib6_drop_pcpu_from() calls fib6_info_release() > which calls fib6_info_destroy_rcu(), so this metrics > will be released twice... And even if there was a leak here, it's illegal to free this metrics memory synchronously since it is RCU protected. That's why it normally goes through fib6_info_destroy_rcu(). Sabrina, I'm going to revert your changes unless I see some progress here by the end of today.