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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1677548895; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GXumw40/iyutB+1Z9nkNOk4cZKA1rPYUrhItU8cLdaE=; b=d9NRIUR/qfM3v0mW0TfMSrBoCUJAaqDbQ18LmGM+jYaoe6uue46AmMQOj02WmuYx8H0giS 75Uwgr2ClR+odZfMUpkgdV90Wf8xuSHKq7p68E2AQr3tx4g8/ci/RX6s+dzB5fj5jLPpDD DbEXYvnYREOVV3GMhfdMBe0u6ETfFNk= 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 X-Rspam-User: X-Rspamd-Queue-Id: 7150540009 X-Rspamd-Server: rspam01 X-Stat-Signature: xksqwhtt9g7hffs61wt9bn51hyfdqoz1 X-HE-Tag: 1677548894-129512 X-HE-Meta: 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 1tY+CYZ/ 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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. > . >