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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 269C9C433E2 for ; Wed, 24 Jun 2020 12:05:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 040DE2088E for ; Wed, 24 Jun 2020 12:05:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390850AbgFXMF5 (ORCPT ); Wed, 24 Jun 2020 08:05:57 -0400 Received: from correo.us.es ([193.147.175.20]:42342 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388522AbgFXMFy (ORCPT ); Wed, 24 Jun 2020 08:05:54 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 8874815C116 for ; Wed, 24 Jun 2020 14:05:52 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 6F7F8DA8EB for ; Wed, 24 Jun 2020 14:05:52 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 5F5B7DA55C; Wed, 24 Jun 2020 14:05:52 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 9792FDA801; Wed, 24 Jun 2020 14:05:49 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Wed, 24 Jun 2020 14:05:49 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id 794F342EF42B; Wed, 24 Jun 2020 14:05:49 +0200 (CEST) Date: Wed, 24 Jun 2020 14:05:49 +0200 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: David Wilder Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, fw@strlen.de, wilder@us.ibm.com, mkubecek@suse.com Subject: Re: [PATCH v1 0/4] iptables: Module unload causing NULL pointer reference. Message-ID: <20200624120549.GA27711@salvia> References: <20200622171014.975-1-dwilder@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200622171014.975-1-dwilder@us.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Jun 22, 2020 at 10:10:10AM -0700, David Wilder wrote: > A crash happened on ppc64le when running ltp network tests triggered by "rmmod iptable_mangle". > > See previous discussion in this thread: https://lists.openwall.net/netdev/2020/06/03/161 . > > In the crash I found in iptable_mangle_hook() that state->net->ipv4.iptable_mangle=NULL causing a NULL pointer dereference. net->ipv4.iptable_mangle is set to NULL in iptable_mangle_net_exit() and called when ip_mangle modules is unloaded. A rmmod task was found running in the crash dump. A 2nd crash showed the same problem when running "rmmod iptable_filter" (net->ipv4.iptable_filter=NULL). > > To fix this I added .pre_exit hook in all iptable_foo.c. The pre_exit will un-register the underlying hook and exit would do the table freeing. The netns core does an unconditional synchronize_rcu after the pre_exit hooks insuring no packets are in flight that have picked up the pointer before completing the un-register. > > These patches include changes for both iptables and ip6tables. > > We tested this fix with ltp running iptables01.sh and iptables01.sh -6 a loop for 72 hours. Series applied, thanks.