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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1C56C7EE23 for ; Tue, 28 Feb 2023 01:48:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229884AbjB1BsS (ORCPT ); Mon, 27 Feb 2023 20:48:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229679AbjB1BsQ (ORCPT ); Mon, 27 Feb 2023 20:48:16 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 111CEDBD5 for ; Mon, 27 Feb 2023 17:48:15 -0800 (PST) Received: from dggpemm100009.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4PQgFB1Xt9zKqGN; Tue, 28 Feb 2023 09:46:06 +0800 (CST) Received: from [10.174.179.24] (10.174.179.24) by dggpemm100009.china.huawei.com (7.185.36.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Tue, 28 Feb 2023 09:48:03 +0800 Subject: Re: [PATCH RFC] arm64/vmalloc: use module region only for module_alloc() if CONFIG_RANDOMIZE_BASE is set To: Ard Biesheuvel , Linux regressions mailing list References: <20221227092634.445212-1-liushixin2@huawei.com> <20230129134147.f19ca0641f1133f3e3bc185b@linux-foundation.org> <20230131150644.GA2605@willie-the-truck> <20230131150750.GB2605@willie-the-truck> <20230207112940.GA12147@willie-the-truck> <8c287b1d-476c-7b00-27f6-76c3a1a5fd46@leemhuis.info> CC: Andrew Morton , Catalin Marinas , Uladzislau Rezki , Christoph Hellwig , , , , Will Deacon From: Liu Shixin Message-ID: <856fa1a1-cecd-a7b7-a6b0-3e3c8fedda47@huawei.com> Date: Tue, 28 Feb 2023 09:48:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.24] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm100009.china.huawei.com (7.185.36.113) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/2/28 0:14, Ard Biesheuvel wrote: > On Mon, 27 Feb 2023 at 16:08, Linux regression tracking (Thorsten > Leemhuis) wrote: >> [CCing the regression list, as it should be in the loop for regressions: >> https://docs.kernel.org/admin-guide/reporting-regressions.html] >> >> On 07.02.23 12:29, Will Deacon wrote: >>> On Tue, Jan 31, 2023 at 05:03:32PM +0100, Ard Biesheuvel wrote: >>>> On Tue, 31 Jan 2023 at 16:07, Will Deacon wrote: >>>>> On Tue, Jan 31, 2023 at 03:06:44PM +0000, Will Deacon wrote: >>>>>> On Sun, Jan 29, 2023 at 01:41:47PM -0800, Andrew Morton wrote: >>>>>>> On Sun, 29 Jan 2023 10:44:31 +0800 Liu Shixin wrote: >>>>>>>> On 2022/12/27 17:26, Liu Shixin wrote: >>>>>>>>> After I add a 10GB pmem device, I got the following error message when >>>>>>>>> insert module: >>>>>>>>> >>>>>>>>> insmod: vmalloc error: size 16384, vm_struct allocation failed, >>>>>>>>> mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0 >>>>>>>>> >>>>>>>>> If CONFIG_RANDOMIZE_BASE is set, the module region can be located in the >>>>>>>>> vmalloc region entirely. Although module_alloc() can fall back to a 2GB >>>>>>>>> window if ARM64_MODULE_PLTS is set, the module region is still easily >>>>>>>>> exhausted because the module region is located at bottom of vmalloc region >>>>>>>>> and the vmalloc region is allocated from bottom to top. >>>>>>>>> >>>>>>>>> Skip module region if not calling from module_alloc(). >>>>>>> I'll assume this is for the arm tree. >>>>>>> >>>>>>> Acked-by: Andrew Morton >>>>>> This looks like the same issue previously reported at: >>>>>> >>>>>> https://lore.kernel.org/all/e6a804de-a5f7-c551-ffba-e09d04e438fc@hisilicon.com/ >>>>>> >>>>>> where Ard had a few suggestions but, afaict, they didn't help. >>>>>> >>>> Thanks for the cc. >>>> >>>> So this is a bit clunky, and I wonder whether we wouldn't be better >>>> off just splitting the vmalloc region into two separate regions: one >>>> for the kernel and modules, and one for everything else. That way, we >>>> lose one bit of entropy in the randomized placement, but the default >>>> 48-bit VA space is vast anway, and even on 39-bit VA configs (such as >>>> Android), I seriously doubt that we come anywhere close to exhausting >>>> the vmalloc space today. >>> That sounds like a good idea to me. >>> >>> Liu Shixin -- do you think you could have a go at implementing Ard's >>> suggestion instead? >> Liu Shixin, did you ever look into realizing this idea? >> >> Or was some progress already made and I just missed it? >> > This patch > > https://lore.kernel.org/all/20230223204101.1500373-1-ardb@kernel.org/ > > should fix the issue. > >> I'm asking, as the idea discussed afaics is not only supposed to fix the >> regression you tried to address, but also one that is now three months >> old and stalled since Mid-December -- which is really unfortunate, as >> that's not how regressions should be handled. :-/ > Is it documented anywhere how regressions should be handled? The > mailing list is flooded with hard to reproduce reports from users as > well as automatic fuzzers and build bots, so I don't think it is > entirely unreasonable to move unresponsive reporters to the back of > the queue. > >> But well, it afaik was >> caused by a patch from Ard, so it's obviously not your job to address >> it. But it seems you were working on it. >> > We are all working together here, so please refrain from telling > people what they should or should not be working on. (I am aware that > you probably did not mean it that way, but things tend to get lost in > translation very easily on the mailing list) > > Liu, could you please check whether the linked patch addresses your issue? Thanks, I will try this patch. > > Thanks, > Ard. > . >