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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60A5CE7717F for ; Mon, 16 Dec 2024 15:34:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B89A76B00A8; Mon, 16 Dec 2024 10:34:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B39616B00B3; Mon, 16 Dec 2024 10:34:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 98B186B00B4; Mon, 16 Dec 2024 10:34:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 762DB6B00A8 for ; Mon, 16 Dec 2024 10:34:29 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 25093B0782 for ; Mon, 16 Dec 2024 15:34:29 +0000 (UTC) X-FDA: 82901218134.23.A7F1169 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf26.hostedemail.com (Postfix) with ESMTP id 5A13A14000F for ; Mon, 16 Dec 2024 15:34:04 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=NsNnKDRG; spf=pass (imf26.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1734363246; 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:dkim-signature; bh=EoXThDuzdwSCkju3MJU1hPpxlhHdcR6+6fSsTLqkgM0=; b=UrnTea3p4rl5SqeFzqpvsC953LoOBKEH588U/n18T66t5C1cSleyhPuHnIhhMu8zs0LjQG glvRL+ey1ze5rXCWvL5715IDLcQgtGIsPWyPFSB0c97dlyDkJCFNfkGVHXo4eVN+udy7k+ 8llue4rJsIhjOx6A+smFNf2Pj3wRY+Q= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=NsNnKDRG; spf=pass (imf26.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1734363246; a=rsa-sha256; cv=none; b=AEH/NvJSPWTj/xP18j8apCYRkXNWl2bfUrnYjV6GtAJ/gLhV4B1m0tgWBA4/hmguCYv2ep qNFqxH64bS6duWJJ9sMnuZegMlcN2yFDzCY1nDxO7GDwirKgJrAfV3B6MFj3zVU8dzYsh2 zousyjyHkzbX6ejOo9yPQISTlnP9+wo= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1734363266; 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=EoXThDuzdwSCkju3MJU1hPpxlhHdcR6+6fSsTLqkgM0=; b=NsNnKDRGfGw+tSHHNQQLRIGhFF8jhwGwTwpNsbWzqdO37tbD0yb48flKkNq0b0Xc2oJtUp dmjFkPqwgAxlS8df0OUQCZCkRN8B2GaBaIqGrYEyR2ywmFkgHSCfY5hi3Xzw0XyENxyRkL h5O5u5KChW3gaLG2WDbVYY1ZmfpAYFI= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-501-qH2QR05ZMF2_C7oBKj7W-w-1; Mon, 16 Dec 2024 10:34:24 -0500 X-MC-Unique: qH2QR05ZMF2_C7oBKj7W-w-1 X-Mimecast-MFC-AGG-ID: qH2QR05ZMF2_C7oBKj7W-w Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-38639b4f19cso2990193f8f.0 for ; Mon, 16 Dec 2024 07:34:24 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734363263; x=1734968063; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=EoXThDuzdwSCkju3MJU1hPpxlhHdcR6+6fSsTLqkgM0=; b=dRIyCw8EsG9Jvb2GXEx8bmcVv9f7tbRIop6w02bwmIU+NT7SY/Jfd0ivc6w4E7dHEb YsCeDa74qdG66urnkzTZp+WIa7/gyL3Neoakor4a6YSbxHhSAJ+Ivls1RNLPgk3P7h5Q 9vsK4klUWoBN/E0ww8D0s18cFajgRDF/gqv5+yTqxT5HTlQBcNme8lhp422v6ftxontl 8nQ+rdUde10qFMcZtmOBq4p6U30+ZebfzHmTvlLUoU1ENMX1tzfP98Ysx1DFEsI1w4qa MQaM4cu+5A854sUj+cKQaSHCaI9jBjeWazDisBYEAX8rduaB938CwNUxfzkioqly7Qd+ uM4Q== X-Gm-Message-State: AOJu0Yy7oEbyxgr2NG16ZBM2vwATVSLrMwqIzFtpkRC1fQoSnq8UxYr0 Kusa9+Do0h6VbiNxogLO7OUU/GB0vjgt0/90FCx1gEC0c2rbvn7JziyOdE6kpL2pdK2tqHAfOQb ChSFdOx9yv6pP59R6SOX905q6nh4uRjoC7yV4X2hpuU0IzudO X-Gm-Gg: ASbGncvOB3bfGe8eyR6NEspWBgti0O85UYYKPk+Vif6moMhSZCAZaGKWJUW+F/ZQywE SWQqE8nXUZPym0AY4Np8MwMefm7OyyqIhSo9mTLpCgt1bYfaySwDdmUBO435oQb0El32U1blbRX 94Z+7/NoPzXHlR4KW93z492B0xWfbpCC4jNGIK2lzioQr3pJVZyMU5/IMadmc0WjNGo2/ekdXT4 Ie0Dh7R3arfea+dpK7kN6dBV37MHDBwRiWmNmJMV9b55JAF+MRxIBrU/oGzggUmprFrfmTJ8Qgl mwRQ+BGrZ8LvKffbU+twg6n3zwYYeOoE3pFhHPm1aeqX7m1/nA8bS4Ka9U5hqcy2GWs/pgvhoW/ OnVz7dsdk X-Received: by 2002:a5d:598e:0:b0:385:ebaf:3824 with SMTP id ffacd0b85a97d-38880ae148fmr12994367f8f.27.1734363263592; Mon, 16 Dec 2024 07:34:23 -0800 (PST) X-Google-Smtp-Source: AGHT+IEzxyqAPYCNK4zV8bCzmuyObuMX2QNbxU0jtpmqKD4rttBfJUzSfWVcLwa4zTdhiE5xVDgKog== X-Received: by 2002:a5d:598e:0:b0:385:ebaf:3824 with SMTP id ffacd0b85a97d-38880ae148fmr12994330f8f.27.1734363263195; Mon, 16 Dec 2024 07:34:23 -0800 (PST) Received: from ?IPV6:2003:cb:c72a:f600:c577:b537:f52a:b994? (p200300cbc72af600c577b537f52ab994.dip0.t-ipconnect.de. [2003:cb:c72a:f600:c577:b537:f52a:b994]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-388c8015f77sm8388163f8f.26.2024.12.16.07.34.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Dec 2024 07:34:22 -0800 (PST) Message-ID: <8e59d2bd-77d3-41bc-83b7-532b018db4e2@redhat.com> Date: Mon, 16 Dec 2024 16:34:21 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: hugetlb: independent PMD page table shared count To: Liu Shixin , Andrew Morton , Muchun Song , Kenneth W Chen , Kefeng Wang , Nanyong Sun Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20241214104401.1052550-1-liushixin2@huawei.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz 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+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241214104401.1052550-1-liushixin2@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ij7fVudNAOmgpV9yvd7qvzDzzlcJew32SkiJjj0dc5s_1734363264 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Stat-Signature: 735kgmw4ifsgreabhefhrj66ugcqhfph X-Rspamd-Queue-Id: 5A13A14000F X-Rspam-User: X-HE-Tag: 1734363244-17259 X-HE-Meta: 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 NlzrmZVY OygPO/suM4MpH2rLuruCsPxlONiHhfVPLSj064ePMAgdOe7w2g71RS5XXrdzATcsP2gwHFWlWph5MGzEWR8o4Yjl1TAp7XIhesNCOXZRuSiINvKhy3K3FJ4OTKzl4/dofB1nUH5a2GN5FfMebzB+/SohWFiSbiAkJxVYiueefOLbID4JHF3Y52HgJUvDZX6dN5anHeC0VfwykTAnf7KWITxWfVkeGaVywrlZABMTMHOcJYSmYT6DuDb7YCn1bafu+VMPtXCuXStPX8ifL7mMEeKze5F7R2n3KMJJvQ535AT/3GUiv/U2oziJEff5SPIjAMTMQg+qHuVlL1IY4E1yxxIkK0eFa294msxg2ePcsb9YvR2PsFZ/XdE5o2C+c//qoQamSBncQS+cCvis= 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: List-Subscribe: List-Unsubscribe: On 14.12.24 11:44, Liu Shixin wrote: > The folio refcount may be increased unexpectly through try_get_folio() by > caller such as split_huge_pages. In huge_pmd_unshare(), we use refcount to > check whether a pmd page table is shared. The check is incorrect if the > refcount is increased by the above caller, and this can cause the page > table leaked: Are you sure it is "leaked" ? I assume what happens is that we end up freeing a page table without calling its constructor. That's why page freeing code complains about "nonzero mapcount" (overlayed by something else). > > BUG: Bad page state in process sh pfn:109324 > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x66 pfn:0x109324 > flags: 0x17ffff800000000(node=0|zone=2|lastcpupid=0xfffff) > page_type: f2(table) > raw: 017ffff800000000 0000000000000000 0000000000000000 0000000000000000 > raw: 0000000000000066 0000000000000000 00000000f2000000 0000000000000000 > page dumped because: nonzero mapcount > ... > CPU: 31 UID: 0 PID: 7515 Comm: sh Kdump: loaded Tainted: G B 6.13.0-rc2master+ #7 > Tainted: [B]=BAD_PAGE > Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 > Call trace: > show_stack+0x20/0x38 (C) > dump_stack_lvl+0x80/0xf8 > dump_stack+0x18/0x28 > bad_page+0x8c/0x130 > free_page_is_bad_report+0xa4/0xb0 > free_unref_page+0x3cc/0x620 > __folio_put+0xf4/0x158 > split_huge_pages_all+0x1e0/0x3e8 > split_huge_pages_write+0x25c/0x2d8 > full_proxy_write+0x64/0xd8 > vfs_write+0xcc/0x280 > ksys_write+0x70/0x110 > __arm64_sys_write+0x24/0x38 > invoke_syscall+0x50/0x120 > el0_svc_common.constprop.0+0xc8/0xf0 > do_el0_svc+0x24/0x38 > el0_svc+0x34/0x128 > el0t_64_sync_handler+0xc8/0xd0 > el0t_64_sync+0x190/0x198 > > The issue may be triggered by damon, offline_page, page_idle etc. which > will increase the refcount of page table. Right, many do have a racy folio_test_lru() check in there, that prevents "most of the harm", but not all of them. -- Cheers, David / dhildenb