From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f176.google.com (mail-pd0-f176.google.com [209.85.192.176]) by kanga.kvack.org (Postfix) with ESMTP id EB6D76B0031 for ; Sat, 8 Feb 2014 19:35:04 -0500 (EST) Received: by mail-pd0-f176.google.com with SMTP id w10so4644749pde.7 for ; Sat, 08 Feb 2014 16:35:04 -0800 (PST) Received: from smtp.gentoo.org (dev.gentoo.org. [2001:470:ea4a:1:214:c2ff:fe64:b2d3]) by mx.google.com with ESMTPS id q5si10115592pae.56.2014.02.08.16.35.03 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Feb 2014 16:35:03 -0800 (PST) Message-ID: <52F6CD33.80607@gentoo.org> Date: Sat, 08 Feb 2014 19:34:59 -0500 From: Richard Yao MIME-Version: 1.0 Subject: Re: [V9fs-developer] finit_module broken on 9p because kernel_read doesn't work? References: <20140207195555.GA18916@nautica> <52F66641.4040405@gentoo.org> <52F671D0.1060907@gentoo.org> <52F68299.1040305@gentoo.org> <52F68528.30104@gentoo.org> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wXEtDWek31gA6pWJMPI1kXrGJIn8hqMoE" Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: Dominique Martinet , Will Deacon , V9FS Developers , Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , Rusty Russell , "linux-mm@kvack.org" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --wXEtDWek31gA6pWJMPI1kXrGJIn8hqMoE Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 02/08/2014 02:54 PM, Andy Lutomirski wrote: > On Sat, Feb 8, 2014 at 11:27 AM, Richard Yao wrote: >> On 02/08/2014 02:20 PM, Andy Lutomirski wrote: >>> Are we looking at the same patch? >>> >>> + if (is_vmalloc_or_module_addr(data)) >>> + pages[index++] =3D vmalloc_to_page(data); >>> >>> if (is_vmalloc_or_module_addr(data) && !is_vmalloc_addr(data)), the >>> vmalloc_to_page(data) sounds unhealthy. >>> >>> --Andy >>> >> >> Mainline loads all Linux kernel modules into virtual memory. No >> architecture is known to me where this is not the case. >> >=20 > Hmm. I stand corrected. vmalloc_to_page is safe on module addresses. >=20 > --Andy >=20 I also stand corrected. After you poked me on this, I sent this patch with a second patch to export is_vmalloc_or_module_addr() to Linus Torvalds, who wrote is_vmalloc_or_module_addr(). He provided a very concise explanation why is_vmalloc_addr() is not only safe, but preferabl= e: https://lkml.org/lkml/2014/2/8/272 I have resubmitted it with that change. I expect it to be merged soon. --wXEtDWek31gA6pWJMPI1kXrGJIn8hqMoE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJS9s05AAoJECDuEZm+6Exk3MAP/3y5XlU0+kMVGHljNaGvZ08L 8RHksmyO8/FB6tdcMU7wTjJ8Ar8ksU+IAo5Bk/dXexEGsUk2e4PQvj9xEoseOCnD /jDs5TGdRw5nb52SwWVRWy1/uFXQwB5y4GJqbpOcxmYwXxib7Y/e7J3+UxobKQVe LImtVecNeIDdl7E0ZCxW5tmOrayxC3Zt2d0xt1kGUZNRISFGXJgORYGanpNcXf+p OT3+YZHd2mJQwOB9xR0YetxFNUOYdCwt04R+eKqvLi4hd5cE2veYOwHaPO/8TREv nhbFhZStKC4Ymd/PyQLqvrfIVb0fxtbTzRKLnnPnUmrkxcVS+gtpkdRYN1PNdyJp y+8aIWFbQcHEs+5TKrKW3TdI+SZLk3Jd0oIYPyuodKGWSLHXUPly5RYwqxeKI0M3 zSw4uQjKdGCL79omwBEBpyGLZrv+P/r2yu/hSjSJHx1idLJaGAdOgajCQtB6cVdf KSJ6tEGC14rsBY2qa3H3dKd7Ag4ilwYkDpgTuSTU1LiXhWfsvY3QEsYrBIUAXtA6 RLbyqDkKFtXkQzEUjMU6XWwW+mqbSzwpntra8/R8QGt6MAT0j9z/p0NyvLfu4UMN 5I/L4GLwHDaP4Up5o11BkTrTlPWfXbxucwEbTJpBUbhrmI+YTNkceoVrHy+Mt7kw QIjST0nmy+RjBRxyCe/6 =9u6t -----END PGP SIGNATURE----- --wXEtDWek31gA6pWJMPI1kXrGJIn8hqMoE-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org