From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 744151D2B3D for ; Wed, 23 Oct 2024 18:50:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729709430; cv=none; b=Idqxv7LahMoa6QZZpHlQ0g8lEocBs6RtPrvSzh2M4dCxbGLSUtqkEao36oJC/YKKLEq5b5gEothW3NCJDeeOL/nzVR3Xrslb4g/rMyDsbx458PD8TAB5QPQDM/0X7FLwjS06LRtMgGtubo6Lvf1z8POEmLJe0KXydD6ZZPSMOuY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729709430; c=relaxed/simple; bh=0MSK6pPABqBtmce3T9II/Ylr88oxS22UsdZ+9/3Yzds=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qOb113wHQgBziSqPCzJEr5mkHH9LFLUvaSV0mwpFLOQSTECcRxKzZ2cep1HggnJ6j0mcm1cI+hIh/VSOLbI4lmhKjJLT2b7+rcGm4UL2CbPy+mglVwR0D5a16xz+rtOvdVhWDvVTOvWex5gUNAmtkJm7vXTRG3lm1dJUFFBpt4E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=bXq43cm3; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bXq43cm3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729709427; 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=qmPSKp0YLHjUOyqd82hGayDLVrh/DCNFeJf+SQ6VSaA=; b=bXq43cm3SwGa6aLEwP/BQ44rQWmDFgyYAbCarLDYF6iwukfcB3/gkncDqEu6ozp5YQDPxR e/5fbmvscwceAYgDP47wxmNxJO0RZZsqnmBRztGikND9HwmwZkvv3PNjqNaPtxsxjIgzpw MVG2qI0Qvd8VOd9gXbBqR8V/47ob0SA= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-124-x-f00-H2Ok-K7iY5lr8UcA-1; Wed, 23 Oct 2024 14:50:25 -0400 X-MC-Unique: x-f00-H2Ok-K7iY5lr8UcA-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-37d563a1af4so12145f8f.2 for ; Wed, 23 Oct 2024 11:50:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729709424; x=1730314224; 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=qmPSKp0YLHjUOyqd82hGayDLVrh/DCNFeJf+SQ6VSaA=; b=J3hOoQHFShJjXZ77J9xFXbNVqFQ+17GnO3QpGhR6WR7vkDfS+ZC4M/HWSqWzo/2A/1 XmjwO1uwtPh4lSeriVZEynBvD3wGqZcaTiY4AnsVsQ3sa/0rUd3A6nCVd+eB/6WOvj2/ 9/BfEVNUvSsFyzFzx7oQ8mvIawM3l111edN2oKIz7K0fqCqwwBHtqede/yknG7Hgbn4I qecJv3khybC+P6mkspt0R0JbQX24wxQr7KmYcwvzDhT/UnetFiWzxBcbc1fAaEQCmcC6 rZoqqe3ttNpfWz8sCB4jwwYCBj8rrCXGh3loVGoVXOl84c6Z1EZfn05lCqBWZaSIlpnL 65nw== X-Forwarded-Encrypted: i=1; AJvYcCUz5wLqrRCrHqkZ5AjCiUZsL9QZgCiLx2SBx1lmY6M6PxSlpnmlkgoFCgUdC7NDgWKl8YGHNcgLMfZXm30=@vger.kernel.org X-Gm-Message-State: AOJu0Yz6gsMKVOzS1LH5OmZfEXM+so/tUES/rYeIPdjNv9ah1TCA2z+z Gsi/K1vg9Dc/Fq4z5EsI8gRnBhB5tvjY+IOK8hH/WnCX9xJfqEF1t/w6MXUVD/9zEGFSXTYMP4Y Gvgglene5fktk0/0NXoO/RloSsTRFH+Y0SbRLvffdQkhLuJyVwgjFwLhz3NbWZg== X-Received: by 2002:a05:6000:dd1:b0:37d:4cd5:ffec with SMTP id ffacd0b85a97d-37efcef5609mr2226616f8f.2.1729709424651; Wed, 23 Oct 2024 11:50:24 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGCB1tgfWSe/u39zeAbh2oZnmODTCV3s3IHynsl+a1e6iFCYYt/Y62YkQ4Pzzw0Zk2XHgEb7w== X-Received: by 2002:a05:6000:dd1:b0:37d:4cd5:ffec with SMTP id ffacd0b85a97d-37efcef5609mr2226587f8f.2.1729709424224; Wed, 23 Oct 2024 11:50:24 -0700 (PDT) Received: from ?IPV6:2003:cb:c70c:cd00:c139:924e:3595:3b5? (p200300cbc70ccd00c139924e359503b5.dip0.t-ipconnect.de. [2003:cb:c70c:cd00:c139:924e:3595:3b5]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43186bfcfd0sm23625305e9.26.2024.10.23.11.50.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 23 Oct 2024 11:50:23 -0700 (PDT) Message-ID: <99d0e61b-9408-490c-8634-f44cb2487d96@redhat.com> Date: Wed, 23 Oct 2024 20:50:21 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: avoid VM_BUG_ON when try to map an anon large folio to zero page. To: Zi Yan , linux-mm@kvack.org, Andrew Morton Cc: usamaarif642@gmail.com, baohua@kernel.org, cerasuolodomenico@gmail.com, corbet@lwn.net, hannes@cmpxchg.org, kernel-team@meta.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, npache@redhat.com, riel@surriel.com, roman.gushchin@linux.dev, rppt@kernel.org, ryan.roberts@arm.com, ryncsn@gmail.com, shakeel.butt@linux.dev, willy@infradead.org, yuzhao@google.com References: <20241023171236.1122535-1-ziy@nvidia.com> From: David Hildenbrand Content-Language: en-US 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: <20241023171236.1122535-1-ziy@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 23.10.24 19:12, Zi Yan wrote: > An anonymous large folio can be split into non order-0 folios, > try_to_map_unused_to_zeropage() should not VM_BUG_ON compound pages but > just return false. This fixes the crash when splitting anonymous large > folios to non order-0 folios. > > Fixes: b1f202060afe ("mm: remap unused subpages to shared zeropage when splitting isolated thp") > Signed-off-by: Zi Yan > --- > mm/migrate.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index e950fd62607f..7ffdbe078aa7 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -206,7 +206,8 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw, > pte_t newpte; > void *addr; > > - VM_BUG_ON_PAGE(PageCompound(page), page); > + if (PageCompound(page)) > + return false; > VM_BUG_ON_PAGE(!PageAnon(page), page); > VM_BUG_ON_PAGE(!PageLocked(page), page); > VM_BUG_ON_PAGE(pte_present(*pvmw->pte), page); Would read nicer in 2024 when working on folios ;) Acked-by: David Hildenbrand -- Cheers, David / dhildenb