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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 78F57C4724C for ; Thu, 30 Apr 2020 15:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 434EF2076D for ; Thu, 30 Apr 2020 15:48:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726421AbgD3Psi (ORCPT ); Thu, 30 Apr 2020 11:48:38 -0400 Received: from correo.us.es ([193.147.175.20]:40828 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726350AbgD3Psi (ORCPT ); Thu, 30 Apr 2020 11:48:38 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id EFF37DA708 for ; Thu, 30 Apr 2020 17:48:36 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id E087FDA7B2 for ; Thu, 30 Apr 2020 17:48:36 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id D5FB6DA788; Thu, 30 Apr 2020 17:48:36 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id DCBC9B7FF8; Thu, 30 Apr 2020 17:48:34 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Thu, 30 Apr 2020 17:48:34 +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 C170742EFB8D; Thu, 30 Apr 2020 17:48:34 +0200 (CEST) Date: Thu, 30 Apr 2020 17:48:34 +0200 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Phil Sutter , netfilter-devel@vger.kernel.org Subject: Re: [iptables PATCH v2 00/18] iptables: introduce cache evaluation phase Message-ID: <20200430154834.GA4180@salvia> References: <20200428121013.24507-1-phil@nwl.cc> <20200429213609.GA24368@salvia> <20200430135300.GK15009@orbyte.nwl.cc> <20200430150831.GA2267@salvia> <20200430152606.GM15009@orbyte.nwl.cc> <20200430154440.GA3999@salvia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200430154440.GA3999@salvia> User-Agent: Mutt/1.10.1 (2018-07-13) X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Thu, Apr 30, 2020 at 05:44:40PM +0200, Pablo Neira Ayuso wrote: > On Thu, Apr 30, 2020 at 05:26:07PM +0200, Phil Sutter wrote: > [...] > > > BTW, this cache consistency check > > > > > > commit 200bc399651499f502ac0de45f4d4aa4c9d37ab6 > > > Author: Phil Sutter > > > Date: Fri Mar 13 13:02:12 2020 +0100 > > > > > > nft: cache: Fix iptables-save segfault under stress > > > > > > is already restored in this series, right? > > > > Yes, IIRC this was the reason why I got a merge conflict upon rebase. > > But the problem shouldn't exist with the new logic: We fetch cache just > > once, so there is no cache update (and potential cache free) happening > > while iterating through chain lists or anything. > > Still another process might be competing to update the ruleset, right? I mean this case: - mnl_genid_get(h, &genid_stop); - if (genid_start != genid_stop) { - flush_chain_cache(h, NULL); - goto retry; - } if the cache is inconsistent (another process stepped in and updated the ruleset), the discard this cache and fetch it again.