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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 4E334C43381 for ; Tue, 12 Mar 2019 18:23:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E00D32087C for ; Tue, 12 Mar 2019 18:23:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E00D32087C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7F6298E0003; Tue, 12 Mar 2019 14:23:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7A5358E0002; Tue, 12 Mar 2019 14:23:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 66DF88E0003; Tue, 12 Mar 2019 14:23:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) by kanga.kvack.org (Postfix) with ESMTP id 3B86E8E0002 for ; Tue, 12 Mar 2019 14:23:57 -0400 (EDT) Received: by mail-qt1-f199.google.com with SMTP id s8so3067802qth.18 for ; Tue, 12 Mar 2019 11:23:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :references:from:openpgp:autocrypt:organization:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=lrzRuOwX8mL9GtniwEJab8F6fOP/UJfwqTuK7x3cgVE=; b=AG0e967kAUuNELslz1R9HJFTmHStds9x6XK/DPksKSpibnQBP3C+s7/GgCSdE3kqXg a2D9ZQ9YN5MhEMYfO/VFdMvgPFGfRvtIWP62dQXi8a39z4jUi+qWuj87G9nMq2smupOk yLLzXz6G0rTP+QIPINmyix9i2RF+NxpfyKKfv/CwyATRNPLUgKchZuXuikFhjdiAUCXY Kbd61WgPdjEyQm/aQ0F6zQ08wCEH9q9hTgEyEWZqyFBpjKtkJbiLtN4h3ALdy7VyXDq2 Fak4i1WSzkXtDHRwLfC42UD99Cliy6psL3Dr1gj7cI623SjZz/oUnALKfJtxPIo6coHR fMGQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: APjAAAWDDXu7MOZra/RYXa9U5x2xXLHCiffSaJ2cf96iNdzuObKMwZZc KswuQ3LIaBjb/kjMNOLYbmi1ExkugQOld92BGRppM7FWEdVQxhWrpeE6kbte7NWXD3zcFNCLElR iIPvkZC/cH82EgWs0tz9suSOQ3mzXyiJMIKHaKFeWvYm8ejXLye1ULEIx755NkKyRWQ== X-Received: by 2002:ac8:2d56:: with SMTP id o22mr3097266qta.321.1552415037007; Tue, 12 Mar 2019 11:23:57 -0700 (PDT) X-Google-Smtp-Source: APXvYqxdZoGpUFg2VL6ZNgQqfulrrBCJMHfpk1k4OoBU/bwnGm0jBKuzQSNKXqDrXetVRq6mrgQG X-Received: by 2002:ac8:2d56:: with SMTP id o22mr3097201qta.321.1552415036178; Tue, 12 Mar 2019 11:23:56 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1552415036; cv=none; d=google.com; s=arc-20160816; b=i8fkuyrK9oWXHruAhCJ5us65UM0BfEaB7uYFETTkTPf+ad3DcaL9S0VQIHD0qhlS60 FvMMeUGQqWa4VAJoMUrdQSrs0rUQ0ujLBu4g2Q413lu09C4v1lD145+AzIbqIWFWnmZ4 lFG7uEqJg/CvazZAgPwfJJ3iEU1cUVTamOYmRHfpybzw+TtFwcI4Tah52oVP7Ow73/N4 82+VKaKRlVRldDRxPQxTyU2ngJyN+QliOblc6/mj2a2DRajvd4Xn3IKXYLc6lFVB1/PO oF0BcZErGVEdR+AyM0LTmakd62h1uR6Fa2c1UD5E6g+Z/blMShoNNAbxScs0lz17p/0N 7ZIA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:organization:autocrypt:openpgp:from :references:cc:to:subject; bh=lrzRuOwX8mL9GtniwEJab8F6fOP/UJfwqTuK7x3cgVE=; b=HFoF5Fr8ZpKimh4sLXfAoxfasmUxfrJqZ9TlWtq6f6rEpFVpvOUtcSQoW5tYLSf4QB PLX5qysFRRDU3tdchzT/O6VoUmmyGsU03beYBQkxFg+s+WVtp6ZJM/KhrGBNngr+Iq3r +twJg6uF8ygG0Sos587yaNGR/mTc5w2bqkD/RYc34d4Sb3fNfgHwAJwb5HcKK6k8IZK4 vWLyHiRw98ytqHrzZs6tKQpXLKJEhmzAtnhP2/FcvTDWnJItF0BLS+q2r8njbR3mriXA YS/dulQ7Gd3p60aF5UVZnDVthjMX+ZlAnZR0xGIpibh9tdN+1AOeypxK0WuGJDXDocec Ju/g== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id l25si5644269qve.97.2019.03.12.11.23.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Mar 2019 11:23:56 -0700 (PDT) Received-SPF: pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E66D5356E4; Tue, 12 Mar 2019 18:23:54 +0000 (UTC) Received: from [10.36.117.44] (ovpn-117-44.ams2.redhat.com [10.36.117.44]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5E1101001DC3; Tue, 12 Mar 2019 18:23:51 +0000 (UTC) Subject: Re: [Xen-devel] xen: Can't insert balloon page into VM userspace (WAS Re: [linux-linus bisection] complete test-arm64-arm64-xl-xsm) To: Boris Ostrovsky , Andrew Cooper , Matthew Wilcox , Julien Grall Cc: Juergen Gross , k.khlebnikov@samsung.com, Stefano Stabellini , Kees Cook , Konrad Rzeszutek Wilk , "VMware, Inc." , osstest service owner , "linux-kernel@vger.kernel.org" , linux-mm@kvack.org, Julien Freche , Nadav Amit , xen-devel@lists.xenproject.org References: <80211e70-5f54-9421-8e8f-2a4fc758ce39@arm.com> <46118631-61d4-adb6-6ffc-4e7c62ea3da9@arm.com> <20190312171421.GJ19508@bombadil.infradead.org> <45323ea0-2a50-8891-830e-e1f8a8ed23ea@citrix.com> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <9a40e1ff-7605-e822-a1d2-502a12d0fba7@redhat.com> Date: Tue, 12 Mar 2019 19:23:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 12 Mar 2019 18:23:55 +0000 (UTC) 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 12.03.19 19:02, Boris Ostrovsky wrote: > On 3/12/19 1:24 PM, Andrew Cooper wrote: >> On 12/03/2019 17:18, David Hildenbrand wrote: >>> On 12.03.19 18:14, Matthew Wilcox wrote: >>>> On Tue, Mar 12, 2019 at 05:05:39PM +0000, Julien Grall wrote: >>>>> On 3/12/19 3:59 PM, Julien Grall wrote: >>>>>> It looks like all the arm test for linus [1] and next [2] tree >>>>>> are now failing. x86 seems to be mostly ok. >>>>>> >>>>>> The bisector fingered the following commit: >>>>>> >>>>>> commit 0ee930e6cafa048c1925893d0ca89918b2814f2c >>>>>> Author: Matthew Wilcox >>>>>> Date: Tue Mar 5 15:46:06 2019 -0800 >>>>>> >>>>>> mm/memory.c: prevent mapping typed pages to userspace >>>>>> Pages which use page_type must never be mapped to userspace as it would >>>>>> destroy their page type. Add an explicit check for this instead of >>>>>> assuming that kernel drivers always get this right. >>>> Oh good, it found a real problem. >>>> >>>>> It turns out the problem is because the balloon driver will call >>>>> __SetPageOffline() on allocated page. Therefore the page has a type and >>>>> vm_insert_pages will deny the insertion. >>>>> >>>>> My knowledge is quite limited in this area. So I am not sure how we can >>>>> solve the problem. >>>>> >>>>> I would appreciate if someone could provide input of to fix the mapping. >>>> I don't know the balloon driver, so I don't know why it was doing this, >>>> but what it was doing was Wrong and has been since 2014 with: >>>> >>>> commit d6d86c0a7f8ddc5b38cf089222cb1d9540762dc2 >>>> Author: Konstantin Khlebnikov >>>> Date: Thu Oct 9 15:29:27 2014 -0700 >>>> >>>> mm/balloon_compaction: redesign ballooned pages management >>>> >>>> If ballooned pages are supposed to be mapped into userspace, you can't mark >>>> them as ballooned pages using the mapcount field. >>>> >>> Asking myself why anybody would want to map balloon inflated pages into >>> user space (this just sounds plain wrong but my understanding to what >>> XEN balloon driver does might be limited), but I assume the easy fix >>> would be to revert >> I suspect the bug here is that the balloon driver is (ab)used for a >> second purpose > > Yes. And its name is alloc_xenballooned_pages(). > Haven't had a look at the code yet, but would another temporary fix be to clear/set PG_offline when allocating/freeing a ballooned page? (assuming here that only such pages will be mapped to user space) -- Thanks, David / dhildenb