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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 BE092C3A5A3 for ; Fri, 30 Aug 2019 06:44:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 89E4321874 for ; Fri, 30 Aug 2019 06:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567147465; bh=BsUr4iBWGVaf2/vVb/vySdKrATJctRsS2mv3PL5m3cY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=vpHye/T4m4GBb4w8VuyzoPLXX8Ufh6GqXzDOF5vXWu4pQ1GKF/tm3hBs8ndIdkO2o FkHLaXLBj4tlg13NWn/NSM+GX+obe8cQQsTLYVtA2uJ0IPr5RuNT4qQAJtWDgSrKz1 /+TwNu95ZLmIFMfGoLMOR8U5yY+EyRkRPFSTvf4A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728079AbfH3GoY (ORCPT ); Fri, 30 Aug 2019 02:44:24 -0400 Received: from mx2.suse.de ([195.135.220.15]:47740 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726510AbfH3GoY (ORCPT ); Fri, 30 Aug 2019 02:44:24 -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 48227ABC4; Fri, 30 Aug 2019 06:44:22 +0000 (UTC) Date: Fri, 30 Aug 2019 08:44:21 +0200 From: Michal Hocko To: Yunsheng Lin Cc: will@kernel.org, akpm@linux-foundation.org, rppt@linux.ibm.com, anshuman.khandual@arm.com, adobriyan@gmail.com, cai@lca.pw, robin.murphy@arm.com, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com Subject: Re: [PATCH] arm64: numa: check the node id before accessing node_to_cpumask_map Message-ID: <20190830064421.GS28313@dhcp22.suse.cz> References: <1567131991-189761-1-git-send-email-linyunsheng@huawei.com> <20190830055528.GO28313@dhcp22.suse.cz> <49b86da7-f114-27c2-463a-9bf5082ac197@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49b86da7-f114-27c2-463a-9bf5082ac197@huawei.com> 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 Fri 30-08-19 14:35:26, Yunsheng Lin wrote: > On 2019/8/30 13:55, Michal Hocko wrote: > > On Fri 30-08-19 10:26:31, Yunsheng Lin wrote: > >> Some buggy bios may not set the device' numa id, and dev_to_node > >> will return -1, which may cause global-out-of-bounds error > >> detected by KASAN. > > > > Why should we workaround a buggy bios like that? Is it so widespread and > > no BIOS update available? Also, why is this arm64 specific? > > For our case, there is BIOS update available. I just thought it might > be better to protect from this case when BIOS has not implemented the > device' numa id setting feature or the feature from BIOS has some bug. > > It is not arm64 specific, right now I only have arm64 board. If it is > ok to protect this from the buggy BIOS, maybe all other arch can be > changed too. If we are to really care then this should be consistent among architectures IMHO. But I am not really sure this is really worth it. The code is quite old and I do not really remember any reports. > >> This patch changes cpumask_of_node to return cpu_none_mask if the > >> node is not valid, and sync the cpumask_of_node between the > >> cpumask_of_node function in numa.h and numa.c. > > > > Why? > > When CONFIG_DEBUG_PER_CPU_MAPS is defined, the cpumask_of_node() in > numa.c is used, if not, the cpumask_of_node() in numa.h is used. > > I am not sure why there is difference between them, and it is there > when since the below commit: > 1a2db300348b ("arm64, numa: Add NUMA support for arm64 platforms.") > > I synced them to keep them consistent whether CONFIG_DEBUG_PER_CPU_MAPS > is defined. Such a change should be made in a separate patch with a full clarification/justification. From the above it is still not clear why this is needed though. > >> Signed-off-by: Yunsheng Lin > >> --- > >> arch/arm64/include/asm/numa.h | 6 ++++++ > >> arch/arm64/mm/numa.c | 2 +- > >> 2 files changed, 7 insertions(+), 1 deletion(-) > >> > >> diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h > >> index 626ad01..da891ed 100644 > >> --- a/arch/arm64/include/asm/numa.h > >> +++ b/arch/arm64/include/asm/numa.h > >> @@ -25,6 +25,12 @@ const struct cpumask *cpumask_of_node(int node); > >> /* Returns a pointer to the cpumask of CPUs on Node 'node'. */ > >> static inline const struct cpumask *cpumask_of_node(int node) > >> { > >> + if (node >= nr_node_ids || node < 0) > >> + return cpu_none_mask; > >> + > >> + if (!node_to_cpumask_map[node]) > >> + return cpu_online_mask; > >> + > >> return node_to_cpumask_map[node]; > >> } > >> #endif > >> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c > >> index 4f241cc..3846313 100644 > >> --- a/arch/arm64/mm/numa.c > >> +++ b/arch/arm64/mm/numa.c > >> @@ -46,7 +46,7 @@ EXPORT_SYMBOL(node_to_cpumask_map); > >> */ > >> const struct cpumask *cpumask_of_node(int node) > >> { > >> - if (WARN_ON(node >= nr_node_ids)) > >> + if (WARN_ON(node >= nr_node_ids || node < 0)) > >> return cpu_none_mask; > >> > >> if (WARN_ON(node_to_cpumask_map[node] == NULL)) > >> -- > >> 2.8.1 > > -- Michal Hocko SUSE Labs