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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 E899BCA9EC5 for ; Wed, 30 Oct 2019 10:22:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB14620874 for ; Wed, 30 Oct 2019 10:22:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572430953; bh=1bLiq4AIluAgC79Z23WkALOU8hnVVbjkbkomiBWoMYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=QnFwkBsiLpboImE2XLQi42IJwP3pK02Uf6CHvYP1qdvY29u1/CBAmuCnuf4ZG/7WA F4p5lEqoPbDQzWWExdVazJZuGTXjgx63ZCZVJ3TIEOo/nAkBTbhtiVvbNKuxuR8m9a 2TKUWSPryq74aqt+znL1Eyfofh9NkInTwLp9Er18= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726728AbfJ3KWc (ORCPT ); Wed, 30 Oct 2019 06:22:32 -0400 Received: from mx2.suse.de ([195.135.220.15]:50656 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726069AbfJ3KWb (ORCPT ); Wed, 30 Oct 2019 06:22:31 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8A10AB59F; Wed, 30 Oct 2019 10:22:29 +0000 (UTC) Date: Wed, 30 Oct 2019 11:22:29 +0100 From: Michal Hocko To: Peter Zijlstra Cc: Yunsheng Lin , catalin.marinas@arm.com, will@kernel.org, mingo@redhat.com, bp@alien8.de, rth@twiddle.net, ink@jurassic.park.msu.ru, mattst88@gmail.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, heiko.carstens@de.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, ralf@linux-mips.org, paul.burton@mips.com, jhogan@kernel.org, jiaxun.yang@flygoat.com, chenhc@lemote.com, akpm@linux-foundation.org, rppt@linux.ibm.com, anshuman.khandual@arm.com, tglx@linutronix.de, cai@lca.pw, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com, x86@kernel.org, dave.hansen@linux.intel.com, luto@kernel.org, len.brown@intel.com, axboe@kernel.dk, dledford@redhat.com, jeffrey.t.kirsher@intel.com, linux-alpha@vger.kernel.org, naveen.n.rao@linux.vnet.ibm.com, mwb@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, tbogendoerfer@suse.de, linux-mips@vger.kernel.org, rafael@kernel.org, gregkh@linuxfoundation.org, bhelgaas@google.com, linux-pci@vger.kernel.org, rjw@rjwysocki.net, lenb@kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH v7] numa: make node_to_cpumask_map() NUMA_NO_NODE aware Message-ID: <20191030102229.GY31513@dhcp22.suse.cz> References: <1572428068-180880-1-git-send-email-linyunsheng@huawei.com> <20191030101449.GW4097@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191030101449.GW4097@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 30-10-19 11:14:49, Peter Zijlstra wrote: > On Wed, Oct 30, 2019 at 05:34:28PM +0800, Yunsheng Lin wrote: > > When passing the return value of dev_to_node() to cpumask_of_node() > > without checking if the device's node id is NUMA_NO_NODE, there is > > global-out-of-bounds detected by KASAN. > > > > From the discussion [1], NUMA_NO_NODE really means no node affinity, > > which also means all cpus should be usable. So the cpumask_of_node() > > should always return all cpus online when user passes the node id as > > NUMA_NO_NODE, just like similar semantic that page allocator handles > > NUMA_NO_NODE. > > > > But we cannot really copy the page allocator logic. Simply because the > > page allocator doesn't enforce the near node affinity. It just picks it > > up as a preferred node but then it is free to fallback to any other numa > > node. This is not the case here and node_to_cpumask_map will only restrict > > to the particular node's cpus which would have really non deterministic > > behavior depending on where the code is executed. So in fact we really > > want to return cpu_online_mask for NUMA_NO_NODE. > > > > Also there is a debugging version of node_to_cpumask_map() for x86 and > > arm64, which is only used when CONFIG_DEBUG_PER_CPU_MAPS is defined, this > > patch changes it to handle NUMA_NO_NODE as normal node_to_cpumask_map(). > > > > [1] https://lkml.org/lkml/2019/9/11/66 > > Signed-off-by: Yunsheng Lin > > Suggested-by: Michal Hocko > > Acked-by: Michal Hocko > > Acked-by: Paul Burton # MIPS bits > > Still: > > Nacked-by: Peter Zijlstra (Intel) Do you have any other proposal that doesn't make any wild guesses about which node to use instead of the undefined one? -- Michal Hocko SUSE Labs