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_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 825DDC43381 for ; Thu, 21 Feb 2019 04:11:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F1B42147A for ; Thu, 21 Feb 2019 04:11:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726974AbfBUELy (ORCPT ); Wed, 20 Feb 2019 23:11:54 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:60076 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726359AbfBUELx (ORCPT ); Wed, 20 Feb 2019 23:11:53 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (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 243F812DE57F5; Wed, 20 Feb 2019 20:11:53 -0800 (PST) Date: Wed, 20 Feb 2019 20:11:52 -0800 (PST) Message-Id: <20190220.201152.690801599680073310.davem@davemloft.net> To: xiyou.wangcong@gmail.com Cc: netdev@vger.kernel.org, bugs@abtelecom.ro, ben@decadent.org.uk, jhs@mojatatu.com, jiri@resnulli.us Subject: Re: [Patch net-next 1/2] net_sched: fix a race condition in tcindex_destroy() From: David Miller In-Reply-To: <20190216185827.21535-1-xiyou.wangcong@gmail.com> References: <20190216185827.21535-1-xiyou.wangcong@gmail.com> 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]); Wed, 20 Feb 2019 20:11:53 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Cong Wang Date: Sat, 16 Feb 2019 10:58:26 -0800 > (cherry picked from commit 8015d93ebd27484418d4952284fd02172fa4b0b2) > > tcindex_destroy() invokes tcindex_destroy_element() via > a walker to delete each filter result in its perfect hash > table, and tcindex_destroy_element() calls tcindex_delete() > which schedules tcf RCU works to do the final deletion work. > Unfortunately this races with the RCU callback > __tcindex_destroy(), which could lead to use-after-free as > reported by Adrian. > > Fix this by migrating this RCU callback to tcf RCU work too, > as that workqueue is ordered, we will not have use-after-free. > > Note, we don't need to hold netns refcnt because we don't call > tcf_exts_destroy() here. > > Fixes: 27ce4f05e2ab ("net_sched: use tcf_queue_work() in tcindex filter") > Reported-by: Adrian > Cc: Ben Hutchings > Cc: Jamal Hadi Salim > Cc: Jiri Pirko > Signed-off-by: Cong Wang Applied.