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 2CC9BC021AA for ; Wed, 19 Feb 2025 18:30:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A661A280258; Wed, 19 Feb 2025 13:30:43 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A161F280257; Wed, 19 Feb 2025 13:30:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B763280258; Wed, 19 Feb 2025 13:30:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 17ABE280257 for ; Wed, 19 Feb 2025 13:30:42 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 02EE3C1D0C for ; Wed, 19 Feb 2025 18:30:41 +0000 (UTC) X-FDA: 83137535124.06.5ED6C54 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf26.hostedemail.com (Postfix) with ESMTP id A474A14001E for ; Wed, 19 Feb 2025 18:30:38 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=fHOQwMsP; spf=pass (imf26.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 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=1739989839; a=rsa-sha256; cv=none; b=BDhNUbi04+Y2eAv/X3VwFlvFaPce96gq7CI+YKn4oGeRfFrgHqDtGFdGm39KzB9zvoBdWH cY9laEd20cXYOlvVhM89iX1vFW0UmzfRZhJmBsRQftJMN1Qd891thqP18QvpjCy4uamEcL 72Glc3zlWwDODe1Akh3Xkh1B62+QzHE= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=fHOQwMsP; spf=pass (imf26.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 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=1739989839; 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=GUxWKRG0VCSvGsESeMARr7YP1aIgG0aRXDVRLKiDF+E=; b=vZ2wloNplojlkUZGdaFon4XPywG2yo+Xhog6pCG5S9/c76eMsUZCRzQA8FQESQewJ/giUw i7BJ/J71a2kr5m3nUCxJmRVLryRGx6TFG3Ykg54X7dcK4/oNd9D/4tvOG7VXhN29w+eTsm kGkIcaSM/R7r2RJMRmZ5R9LWLGDU6vY= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739989837; 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=GUxWKRG0VCSvGsESeMARr7YP1aIgG0aRXDVRLKiDF+E=; b=fHOQwMsPzaXba9zPbMWJM1zLlK1FiNZte1Tscm04kf1C/ZmVwO1/fHlkKARFpShDnUqXao EmenW1YUfpUnZ+z8jXXkhEGewkYd8v5qSiEujZqGZlla6Bq+ZqL5KdWJnWuKnWS6z6FwNF iIftc5HGWFMDsLFhGMgMa05stOmUXpk= 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-32-HOdJHhaUMO2qUiheGesXrA-1; Wed, 19 Feb 2025 13:30:36 -0500 X-MC-Unique: HOdJHhaUMO2qUiheGesXrA-1 X-Mimecast-MFC-AGG-ID: HOdJHhaUMO2qUiheGesXrA_1739989835 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-43941ad86d4so248975e9.2 for ; Wed, 19 Feb 2025 10:30:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739989835; x=1740594635; 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=GUxWKRG0VCSvGsESeMARr7YP1aIgG0aRXDVRLKiDF+E=; b=hroKRASCBN4ODdb9Rc6Z3Mw7hcRQZZk8XOWoOLqjuJoAKe8DzeWaCFiFSk67CYPlHS 77hoxPCZO+x0iIPnsFrm3tVhbFdtqie5NZYzd+18Ciz4TY0scMt+XWsYxKPw0GnTlSib eOEJFHhGLk7H3W+0UU6O5FetVMJyHTNzY1dpZGdDXzf5P6BgnNPdDZzux48zPi9D6fSd T+ro6B7fq+OLyoC3WLCNl03F1xDOBUk5NHuQ+n4jTDJo6bRiqt4lxZGZ9UlBFH8dpynl XsdxFXjTBgJ7tNceYatvTP9LsTEk8oFuAWsKCcP30KSVvZfZLb2eUPUqwAaVKWPsSF95 vNRQ== X-Gm-Message-State: AOJu0YwMYET2iBoWEK2jVF8G5moS91azY+0bf+/RBs5zFHLGDgg1+ySB 0eHdDDgNTwtMnassan7YoGYLD6kJABOL8kUN2BY6V5n9KRONKAciLYIDIilGkx1rNN54NdaX77A XEG5p8M+F6SXpyMs+4ooljKXTjrXu0Lt7RxP9NXFDa1XQEpC3 X-Gm-Gg: ASbGncsOWCYRsu7ClkMjKOsQY0U16H5pKyf+tYvy//OjmBEy//vJzPy39UVU9QwKoWI 80ZACWT9B9ATNhdQjoqNfl3QaoIZQqXYbjMLUw+qPaO78TGnb6M0YtOxYV3A6IQwvBZGiuOcCYw GvQ011MMzXv3qLP6kCE+8oQCocDiXNSnQl8DqIxQY/uEma0FxkCx7jd/D3pUmO0gIp1uiq2025b nlCg5r7Plt9y67qBIduddCYnNz9SniUqGiHd4zfTTUUOktgPubDBiSt8TReujVDBEr9goStKZAu hE9EK2AWrXpJzJOzSBv9sNnUwObg3Ow/nbOjebAdDhA2V4/DD7YuKf1Q2sE9J7EtpRlpOZwRlLR 9K7kKLTyxaK1qdjyA2EKtKxDv3nar5UCg X-Received: by 2002:a5d:6c66:0:b0:38d:e3da:8b50 with SMTP id ffacd0b85a97d-38f33f4377bmr21094814f8f.39.1739989834958; Wed, 19 Feb 2025 10:30:34 -0800 (PST) X-Google-Smtp-Source: AGHT+IG2O+yqy2Odr2mRbUqUSlqY+Qx+Bab4Ra7sAZnTNNWRqztSFSUibzCVO0KNTl6F1eVS05VVFg== X-Received: by 2002:a5d:6c66:0:b0:38d:e3da:8b50 with SMTP id ffacd0b85a97d-38f33f4377bmr21094784f8f.39.1739989834548; Wed, 19 Feb 2025 10:30:34 -0800 (PST) Received: from ?IPV6:2003:cb:c712:8400:50d0:d1c1:90d6:e2e0? (p200300cbc712840050d0d1c190d6e2e0.dip0.t-ipconnect.de. [2003:cb:c712:8400:50d0:d1c1:90d6:e2e0]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38f259f7987sm18186597f8f.87.2025.02.19.10.30.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Feb 2025 10:30:34 -0800 (PST) Message-ID: Date: Wed, 19 Feb 2025 19:30:31 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC] mm: Fix kernel BUG when userfaultfd_move encounters swapcache To: Suren Baghdasaryan , Barry Song <21cnbao@gmail.com> Cc: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, zhengtangquan@oppo.com, Barry Song , Andrea Arcangeli , Al Viro , Axel Rasmussen , Brian Geffon , Christian Brauner , Hugh Dickins , Jann Horn , Kalesh Singh , "Liam R . Howlett" , Lokesh Gidra , Matthew Wilcox , Michal Hocko , Mike Rapoport , Nicolas Geoffray , Peter Xu , Ryan Roberts , Shuah Khan , ZhangPeng References: <20250219112519.92853-1-21cnbao@gmail.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: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: AKjfn3NNXLlXDaEKbKRqV-uaskjhyE22eruG4KWnNiU_1739989835 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: A474A14001E X-Stat-Signature: p66s6ckoh86b6c8tukuap3srct6e1bfk X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1739989838-933801 X-HE-Meta: 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 yAmuPq8L 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 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 19.02.25 19:26, Suren Baghdasaryan wrote: > On Wed, Feb 19, 2025 at 3:25 AM Barry Song <21cnbao@gmail.com> wrote: >> >> From: Barry Song >> >> userfaultfd_move() checks whether the PTE entry is present or a >> swap entry. >> >> - If the PTE entry is present, move_present_pte() handles folio >> migration by setting: >> >> src_folio->index = linear_page_index(dst_vma, dst_addr); >> >> - If the PTE entry is a swap entry, move_swap_pte() simply copies >> the PTE to the new dst_addr. >> >> This approach is incorrect because even if the PTE is a swap >> entry, it can still reference a folio that remains in the swap >> cache. >> >> If do_swap_page() is triggered, it may locate the folio in the >> swap cache. However, during add_rmap operations, a kernel panic >> can occur due to: >> page_pgoff(folio, page) != linear_page_index(vma, address) > > Thanks for the report and reproducer! > >> >> $./a.out > /dev/null >> [ 13.336953] page: refcount:6 mapcount:1 mapping:00000000f43db19c index:0xffffaf150 pfn:0x4667c >> [ 13.337520] head: order:2 mapcount:1 entire_mapcount:0 nr_pages_mapped:1 pincount:0 >> [ 13.337716] memcg:ffff00000405f000 >> [ 13.337849] anon flags: 0x3fffc0000020459(locked|uptodate|dirty|owner_priv_1|head|swapbacked|node=0|zone=0|lastcpupid=0xffff) >> [ 13.338630] raw: 03fffc0000020459 ffff80008507b538 ffff80008507b538 ffff000006260361 >> [ 13.338831] raw: 0000000ffffaf150 0000000000004000 0000000600000000 ffff00000405f000 >> [ 13.339031] head: 03fffc0000020459 ffff80008507b538 ffff80008507b538 ffff000006260361 >> [ 13.339204] head: 0000000ffffaf150 0000000000004000 0000000600000000 ffff00000405f000 >> [ 13.339375] head: 03fffc0000000202 fffffdffc0199f01 ffffffff00000000 0000000000000001 >> [ 13.339546] head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 >> [ 13.339736] page dumped because: VM_BUG_ON_PAGE(page_pgoff(folio, page) != linear_page_index(vma, address)) >> [ 13.340190] ------------[ cut here ]------------ >> [ 13.340316] kernel BUG at mm/rmap.c:1380! >> [ 13.340683] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP >> [ 13.340969] Modules linked in: >> [ 13.341257] CPU: 1 UID: 0 PID: 107 Comm: a.out Not tainted 6.14.0-rc3-gcf42737e247a-dirty #299 >> [ 13.341470] Hardware name: linux,dummy-virt (DT) >> [ 13.341671] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) >> [ 13.341815] pc : __page_check_anon_rmap+0xa0/0xb0 >> [ 13.341920] lr : __page_check_anon_rmap+0xa0/0xb0 >> [ 13.342018] sp : ffff80008752bb20 >> [ 13.342093] x29: ffff80008752bb20 x28: fffffdffc0199f00 x27: 0000000000000001 >> [ 13.342404] x26: 0000000000000000 x25: 0000000000000001 x24: 0000000000000001 >> [ 13.342575] x23: 0000ffffaf0d0000 x22: 0000ffffaf0d0000 x21: fffffdffc0199f00 >> [ 13.342731] x20: fffffdffc0199f00 x19: ffff000006210700 x18: 00000000ffffffff >> [ 13.342881] x17: 6c203d2120296567 x16: 6170202c6f696c6f x15: 662866666f67705f >> [ 13.343033] x14: 6567617028454741 x13: 2929737365726464 x12: ffff800083728ab0 >> [ 13.343183] x11: ffff800082996bf8 x10: 0000000000000fd7 x9 : ffff80008011bc40 >> [ 13.343351] x8 : 0000000000017fe8 x7 : 00000000fffff000 x6 : ffff8000829eebf8 >> [ 13.343498] x5 : c0000000fffff000 x4 : 0000000000000000 x3 : 0000000000000000 >> [ 13.343645] x2 : 0000000000000000 x1 : ffff0000062db980 x0 : 000000000000005f >> [ 13.343876] Call trace: >> [ 13.344045] __page_check_anon_rmap+0xa0/0xb0 (P) >> [ 13.344234] folio_add_anon_rmap_ptes+0x22c/0x320 >> [ 13.344333] do_swap_page+0x1060/0x1400 >> [ 13.344417] __handle_mm_fault+0x61c/0xbc8 >> [ 13.344504] handle_mm_fault+0xd8/0x2e8 >> [ 13.344586] do_page_fault+0x20c/0x770 >> [ 13.344673] do_translation_fault+0xb4/0xf0 >> [ 13.344759] do_mem_abort+0x48/0xa0 >> [ 13.344842] el0_da+0x58/0x130 >> [ 13.344914] el0t_64_sync_handler+0xc4/0x138 >> [ 13.345002] el0t_64_sync+0x1ac/0x1b0 >> [ 13.345208] Code: aa1503e0 f000f801 910f6021 97ff5779 (d4210000) >> [ 13.345504] ---[ end trace 0000000000000000 ]--- >> [ 13.345715] note: a.out[107] exited with irqs disabled >> [ 13.345954] note: a.out[107] exited with preempt_count 2 >> >> Fully fixing it would be quite complex, requiring similar handling >> of folios as done in move_present_pte. > > How complex would that be? Is it a matter of adding > folio_maybe_dma_pinned() checks, doing folio_move_anon_rmap() and > folio->index = linear_page_index like in move_present_pte() or > something more? If the entry is pte_swp_exclusive(), and the folio is order-0, it cannot be pinned and we may be able to move it I think. So all that's required is to check pte_swp_exclusive() and the folio size. ... in theory :) Not sure about the swap details. -- Cheers, David / dhildenb