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 BECC52957CD for ; Tue, 17 Jun 2025 09:30:27 +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=1750152629; cv=none; b=q0xCLNjCqLdfTZ4nnJKNnJhW/lrj8UtF3ddb8Sz9eH8M0+5scF7/GRH1kpcOW9JbwILuI5gdp453Xlfkb//9hWxhAdbkyjcEJhFJmGdBnYkB0QKO2Yvq9igiYS006ZAUBgFGVn/MZL2gwyBcLrPhPHkq569FLHA2k4csOEExHhI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750152629; c=relaxed/simple; bh=VsGFuJ30l6CqVRP3jywVJWX2fWTvbWCR93BCpuZBv6I=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=KOcyzoSayyxd2gQKgt8IQXGvu4meMm/5RbYcFEbVoi6nJ+q1vxgPZ02ayZI4n1y8J5F7b7iPWj9FA1hazK3gjNpK5pLJ7GV3FJI4M2XVDZcbKB85mo1/545VD3+d8ILxinzTLmkuf/IQlQJ6sINhwEZSK7M38XOxnkBmmBzGlYc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=V5GvZj85; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="V5GvZj85" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1750152626; 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=AycC/SqlmFtbCkiK+UJFsVg8F5mY3OZuVJE4LIVGke0=; b=V5GvZj85cMVYyTXDJ7amQOXGXFjlyN8mAUKTBMuuuQEI3RPN9p2IvKq6dYgC5Fa9XepOOj HD8aDGmNAn3oXuemf3pdbsjZBELecH/anmpPZ80kNnxlggFgE//AiyZIG/vWi/VZG6QeZD 9p5rR1QOR7ma/eWWb+xhCDWQ5tQ75FI= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-258-6qeSKTtsMY-o3-K46P7lqg-1; Tue, 17 Jun 2025 05:30:24 -0400 X-MC-Unique: 6qeSKTtsMY-o3-K46P7lqg-1 X-Mimecast-MFC-AGG-ID: 6qeSKTtsMY-o3-K46P7lqg_1750152624 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-450787c8626so40917675e9.1 for ; Tue, 17 Jun 2025 02:30:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750152623; x=1750757423; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:references:cc:to:from:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=AycC/SqlmFtbCkiK+UJFsVg8F5mY3OZuVJE4LIVGke0=; b=L8UxynAHSEuR7rcEEPRNXibIA76dKvTvv/pypPneop3Z/wXxe1sSNa9J/8VQy24bIW Ffv0fBE20YGRrxYmFvodI81ZHZZtRdevJbHmcwvI3z7gVmBshcCfQOzkPZ3zq5Gs0vKk 3rh/ZUDzbPfaRmZh+7AqJHmICSIh1XPYJY599RgBOySkegXojBfFliRtkMjAKHLzA3XZ hkkKHFo+1hRgNnvQX7e+E/7w7FZUC1lvUAGLXwnU7JQo7YKoL+JMsSIxFjIsUjwVakeL +GjAAim4cOPKcpkmNoNW7E9zHgULdSBRZSnCoqCWrjDHTuOjvnldmZJQCqwKdKPIXbc2 D2bg== X-Forwarded-Encrypted: i=1; AJvYcCWek2hh3UU1/j3H1NULr7d4Ie7/0qHPCAxTqOp/SQwvpIHnGYZbKuVOoW79Ftu9XhT4lEQvLYItrZO2Skc=@vger.kernel.org X-Gm-Message-State: AOJu0Yw4n3yxVuG6pZhAXJ4+yAlKxiodZC2gDLiAlC0VlJZmjDn3omDm 0C2A1PLSjVDnczeAQz6zx8+N7cWgwj9K1dyInJoCPS327RDhQizUQt1cqVJC6FK7sLe+l0qMUYK YevS8k8mdlfIPVaBCeGwBYQ352zp6/y7Rv2G38MDU3Hk7652vrbnAfEKQar1xRInxzw== X-Gm-Gg: ASbGnctGyp6UJpOKWeqGt8oMuhqRATT9EdEAva76CYq6Omlg1V7ccd91mTyu5aISMbG HNaXD9kRnwqymh9Yus4CKeT+ggFAPlTBxCzGAnsT/wIkrKHRVphyxF6tyZuebPMPBfwOPn1y6be MloJRPZdIb+6DNtVPhg3dRoVColV9h6uaOlluUPtbiZrH1krexdNHoYYb7E/RjfjjqwD+y4TBaJ n6yQJwKq4IR4036RIrcw5+HGW2lbmc7oDtHgIFGLI4jNTZr1HriDOsf0ROBe4rB4aoXDicLBbj2 ZmplTBoAYVxbijgOUyk6L8h0YgF+NhUxQgNMb1WqUPQzxfNaNjOyHbvLU1O9+ywd0E30HDXH+Lf 7qqWGPqZ2ZGRiNYENH89CS4Hgc1ODyWb4SnHEqR6/ze1A5wE= X-Received: by 2002:a05:6000:3109:b0:3a3:7387:3078 with SMTP id ffacd0b85a97d-3a572367b6bmr10595426f8f.4.1750152623488; Tue, 17 Jun 2025 02:30:23 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHzIdOD1Y0VrtNcMDMGER4ExUmFNXEczyRtVtoCy/fV6z201YqQ8+qNgA+yjmzITUoW9nwVOw== X-Received: by 2002:a05:6000:3109:b0:3a3:7387:3078 with SMTP id ffacd0b85a97d-3a572367b6bmr10595381f8f.4.1750152622944; Tue, 17 Jun 2025 02:30:22 -0700 (PDT) Received: from ?IPV6:2003:d8:2f31:700:3851:c66a:b6b9:3490? (p200300d82f3107003851c66ab6b93490.dip0.t-ipconnect.de. [2003:d8:2f31:700:3851:c66a:b6b9:3490]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a568b79f45sm13384674f8f.101.2025.06.17.02.30.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Jun 2025 02:30:22 -0700 (PDT) Message-ID: Date: Tue, 17 Jun 2025 11:30:20 +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 v2 02/14] mm: Filter zone device pages returned from folio_walk_start() From: David Hildenbrand To: Alistair Popple , akpm@linux-foundation.org Cc: linux-mm@kvack.org, gerald.schaefer@linux.ibm.com, dan.j.williams@intel.com, jgg@ziepe.ca, willy@infradead.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, jhubbard@nvidia.com, hch@lst.de, zhang.lyra@gmail.com, debug@rivosinc.com, bjorn@kernel.org, balbirs@nvidia.com, lorenzo.stoakes@oracle.com, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-cxl@vger.kernel.org, dri-devel@lists.freedesktop.org, John@Groves.net, m.szyprowski@samsung.com References: <11dd5b70546ec67593a4bf79f087b113f15d6bb1.1750075065.git-series.apopple@nvidia.com> <6afc2e67-3ecb-41a5-9c8f-00ecd64f035a@redhat.com> 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: <6afc2e67-3ecb-41a5-9c8f-00ecd64f035a@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 17.06.25 11:25, David Hildenbrand wrote: > On 16.06.25 13:58, Alistair Popple wrote: >> Previously dax pages were skipped by the pagewalk code as pud_special() or >> vm_normal_page{_pmd}() would be false for DAX pages. Now that dax pages are >> refcounted normally that is no longer the case, so the pagewalk code will >> start returning them. >> >> Most callers already explicitly filter for DAX or zone device pages so >> don't need updating. However some don't, so add checks to those callers. >> >> Signed-off-by: Alistair Popple >> >> --- >> >> Changes since v1: >> >> - Dropped "mm/pagewalk: Skip dax pages in pagewalk" and replaced it >> with this new patch for v2 >> >> - As suggested by David and Jason we can filter the folios in the >> callers instead of doing it in folio_start_walk(). Most callers >> already do this (see below). >> >> I audited all callers of folio_walk_start() and found the following: >> >> mm/ksm.c: >> >> break_ksm() - doesn't need to filter zone_device pages because the can >> never be KSM pages. >> >> get_mergeable_page() - already filters out zone_device pages. >> scan_get_next_rmap_iterm() - already filters out zone_device_pages. >> >> mm/huge_memory.c: >> >> split_huge_pages_pid() - already checks for DAX with >> vma_not_suitable_for_thp_split() >> >> mm/rmap.c: >> >> make_device_exclusive() - only works on anonymous pages, although >> there'd be no issue with finding a DAX page even if support was extended >> to file-backed pages. >> >> mm/migrate.c: >> >> add_folio_for_migration() - already checks the vma with vma_migratable() >> do_pages_stat_array() - explicitly checks for zone_device folios >> >> kernel/event/uprobes.c: >> >> uprobe_write_opcode() - only works on anonymous pages, not sure if >> zone_device could ever work so add an explicit check >> >> arch/s390/mm/fault.c: >> >> do_secure_storage_access() - not sure so be conservative and add a check >> >> arch/s390/kernel/uv.c: >> >> make_hva_secure() - not sure so be conservative and add a check >> --- >> arch/s390/kernel/uv.c | 2 +- >> arch/s390/mm/fault.c | 2 +- >> kernel/events/uprobes.c | 2 +- >> 3 files changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c >> index b99478e..55aa280 100644 >> --- a/arch/s390/kernel/uv.c >> +++ b/arch/s390/kernel/uv.c >> @@ -424,7 +424,7 @@ int make_hva_secure(struct mm_struct *mm, unsigned long hva, struct uv_cb_header >> return -EFAULT; >> } >> folio = folio_walk_start(&fw, vma, hva, 0); >> - if (!folio) { >> + if (!folio || folio_is_zone_device(folio)) { >> mmap_read_unlock(mm); >> return -ENXIO; >> } >> diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c >> index e1ad05b..df1a067 100644 >> --- a/arch/s390/mm/fault.c >> +++ b/arch/s390/mm/fault.c >> @@ -449,7 +449,7 @@ void do_secure_storage_access(struct pt_regs *regs) >> if (!vma) >> return handle_fault_error(regs, SEGV_MAPERR); >> folio = folio_walk_start(&fw, vma, addr, 0); >> - if (!folio) { >> + if (!folio || folio_is_zone_device(folio)) { >> mmap_read_unlock(mm); >> return; >> } > > Curious, does s390 even support ZONE_DEVICE and could trigger this? Ah, I see you raised this above. Even if it could be triggered (which I don't think), I wonder if there would actually be a problem with zone_device folios in here? I think these two can be dropped for now -- Cheers, David / dhildenb