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=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 06A97C4363C for ; Sun, 4 Oct 2020 21:54:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCEF8206DD for ; Sun, 4 Oct 2020 21:54:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726552AbgJDVy4 (ORCPT ); Sun, 4 Oct 2020 17:54:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726374AbgJDVyz (ORCPT ); Sun, 4 Oct 2020 17:54:55 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4466C0613CE for ; Sun, 4 Oct 2020 14:54:55 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::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 3078912780FC3; Sun, 4 Oct 2020 14:38:07 -0700 (PDT) Date: Sun, 04 Oct 2020 14:54:53 -0700 (PDT) Message-Id: <20201004.145453.1397904175583154013.davem@davemloft.net> To: xiyou.wangcong@gmail.com Cc: netdev@vger.kernel.org, syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com, vladbu@mellanox.com, jhs@mojatatu.com, jiri@resnulli.us Subject: Re: [Patch net] net_sched: check error pointer in tcf_dump_walker() From: David Miller In-Reply-To: <20201002191334.14135-1-xiyou.wangcong@gmail.com> References: <20201002191334.14135-1-xiyou.wangcong@gmail.com> X-Mailer: Mew version 6.8 on Emacs 27.1 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 [2620:137:e000::1:9]); Sun, 04 Oct 2020 14:38:07 -0700 (PDT) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Cong Wang Date: Fri, 2 Oct 2020 12:13:34 -0700 > Although we take RTNL on dump path, it is possible to > skip RTNL on insertion path. So the following race condition > is possible: > > rtnl_lock() // no rtnl lock > mutex_lock(&idrinfo->lock); > // insert ERR_PTR(-EBUSY) > mutex_unlock(&idrinfo->lock); > tc_dump_action() > rtnl_unlock() > > So we have to skip those temporary -EBUSY entries on dump path > too. > > Reported-and-tested-by: syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com > Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together") > Cc: Vlad Buslov > Cc: Jamal Hadi Salim > Cc: Jiri Pirko > Signed-off-by: Cong Wang Applied and queued up for -stable.