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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 AD1A6C33CB1 for ; Wed, 15 Jan 2020 15:55:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 61F782187F for ; Wed, 15 Jan 2020 15:55:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hEyViNdF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61F782187F 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 EC5608E000D; Wed, 15 Jan 2020 10:55:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E74B38E0006; Wed, 15 Jan 2020 10:55:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D176C8E000D; Wed, 15 Jan 2020 10:55:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0095.hostedemail.com [216.40.44.95]) by kanga.kvack.org (Postfix) with ESMTP id B75AE8E0006 for ; Wed, 15 Jan 2020 10:55:11 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 6FCD21F0A for ; Wed, 15 Jan 2020 15:55:11 +0000 (UTC) X-FDA: 76380317622.16.maid67_67758c5e57315 X-HE-Tag: maid67_67758c5e57315 X-Filterd-Recvd-Size: 9572 Received: from us-smtp-1.mimecast.com (us-smtp-2.mimecast.com [207.211.31.81]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Jan 2020 15:55:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579103710; h=from:from: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:autocrypt:autocrypt; bh=ujV0JyilP8tZlry1RydNDIK15qlAZagPiNUh5Ki/kEo=; b=hEyViNdFHHduXnvFcMuEL1boAe11mZGAu2tENHP8XOLMS3O0nJEP+5nrj2/wWkyQwoElhP iddpT5ds4N+AA/lnNDPWTHppf+L+jhcgcaEf6lm7Yf3FHKGP1eTmPb50Kc9n6HzAVS4Bzf PcZrfW6vmOye6tzOi8iUxKiZbHVViyg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-21-zTOom90qNqmIvNzvSsrj1g-1; Wed, 15 Jan 2020 10:55:04 -0500 X-MC-Unique: zTOom90qNqmIvNzvSsrj1g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9BE16194C252; Wed, 15 Jan 2020 15:55:02 +0000 (UTC) Received: from [10.36.118.7] (unknown [10.36.118.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id 82E4960BE0; Wed, 15 Jan 2020 15:55:00 +0000 (UTC) Subject: Re: [PATCH for 4.19-stable 00/25] mm/memory_hotplug: backport of pending stable fixes To: Greg Kroah-Hartman Cc: stable@vger.kernel.org, linux-mm@kvack.org, Oscar Salvador , Michal Hocko , "Aneesh Kumar K . V" , Dan Williams , Andrew Morton , Laurent Vivier , Baoquan He References: <20200115153339.36409-1-david@redhat.com> <20200115153927.GC3881751@kroah.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: <4a09f161-e2f1-b506-f0fd-2d6c4ea1437c@redhat.com> Date: Wed, 15 Jan 2020 16:54:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20200115153927.GC3881751@kroah.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Content-Transfer-Encoding: quoted-printable 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 15.01.20 16:39, Greg Kroah-Hartman wrote: > On Wed, Jan 15, 2020 at 04:33:14PM +0100, David Hildenbrand wrote: >> This is the backport of the following fixes for 4.19-stable: >> >> - a31b264c2b41 ("mm/memory_hotplug: make >> unregister_memory_block_under_nodes() never fail") >> -- Turned out to not only be a cleanup but also a fix Took the wrong one. It's d84f2f5a7552 ("drivers/base/node.c: simplify unregister_memory_block_under_nodes()") >> - 2c91f8fc6c99 ("mm/memory_hotplug: fix try_offline_node()") >> -- Automatic stable backport failed due to missing dependencies. >> - feee6b298916 ("mm/memory_hotplug: shrink zones when offlining memory= ") >> -- Was marked as stable 5.0+ due to the backport complexity,, but it's= also >> relevant for 4.19/4.14. As I have to backport quite some cleanups >> already ... >> >> To minimize manual code changes, I decided to pull in quite some clean= ups. >> Still some manual code changes are necessary (indicated in the individ= ual >> patches). Especially missing arm64 hot(un)plug, missing sub-section ho= tadd >> support, and missing unification of mm/hmm.c and kernel/memremap.c req= uires >> care. >> >> Due to: >> - 4e0d2e7ef14d ("mm, sparse: pass nid instead of pgdat to >> sparse_add_one_section()") >> I need: >> - afe9b36ca890 ("mm/memunmap: don't access uninitialized memmap in >> memunmap_pages()") >> >> Please note that: >> - 4c4b7f9ba948 ("mm/memory_hotplug: remove memory block devices >> before arch_remove_memory()") >> Makes big (e.g., 32TB) machines boot up slower (e.g., 2h vs 10m). Ther= e is >> a performance fix in linux-next, but it does not seem to classify as a >> fix for current RC / stable. >> >> I did quite some testing with hot(un)plug, onlining/offlining of memor= y >> blocks and memory-less/CPU-less NUMA nodes under x86_64 - the same set= of >> tests I run against upstream on a fairly regular basis. I compile-test= ed >> on PowerPC. I did not test any ZONE_DEVICE/HMM thingies. >> >> Let's see what people think - it's a lot of patches. If we want this, >> then I can try to prepare a similar set for 4.4-stable. >=20 > What bug(s) are these trying to fix here? All tackle memory unplug issues, especially when memory was never onlined (or onlining failed), paired with memory unplug. When trying to access garbage memmaps we crash the kernel (e.g., because the derviced pgdat pointer is broken) d84f2f5a7552 ("drivers/base/node.c: simplify unregister_memory_block_under_nodes()") -> https://lore.kernel.org/linux-mm/b2e31976-b07d-11e6-f806-f13f4619be4d@red= hat.com/ "If the memory we are removing was never onlined, get_nid_for_pfn()->pfn_to_nid() will return garbage. Removing will succeed but links will remain in place. [...] We will trigger the BUG_ON(ret) in add_memory_resource(), because link_mem_sections() will return with -EEXIST." 2c91f8fc6c99 ("mm/memory_hotplug: fix try_offline_node()") We might access garbage memmaps on memory unplug and trigger a crash on memory unplug, when trying to offline the node. feee6b298916 ("mm/memory_hotplug: shrink zones when offlining memory") Memory unplug will access garbage memmaps (resulting in crashes) and the zones might not get fixed up properly. Relevant when memory was never onlined, when memory blocks of a DIMM were onlined to different zones, or when memory blocks were re-onlined to different zones. This backports the remaining "don't access uninitialized memmaps"-like fixes. The other ones, were already backported. >=20 > And why would 4.9 and 4.4 care about them? The crashes can be trigger under 4.9 and 4.4. If we decide that we do not care, then this series can be dropped. --=20 Thanks, David / dhildenb