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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B69FC433EF for ; Tue, 29 Mar 2022 15:50:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239016AbiC2Pvv (ORCPT ); Tue, 29 Mar 2022 11:51:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239006AbiC2Pvt (ORCPT ); Tue, 29 Mar 2022 11:51:49 -0400 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F13385BD5; Tue, 29 Mar 2022 08:50:07 -0700 (PDT) Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nZE6V-0004sG-4e; Tue, 29 Mar 2022 11:49:55 -0400 Message-ID: <47936edb3b0f9c9f04f0d0d2e7f38383a22b6a3d.camel@surriel.com> Subject: Re: [PATCH] mm,hwpoison: unmap poisoned page before invalidation From: Rik van Riel To: Oscar Salvador Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com, Miaohe Lin , Naoya Horiguchi , Mel Gorman , Johannes Weiner , Andrew Morton , stable@vger.kernel.org Date: Tue, 29 Mar 2022 11:49:53 -0400 In-Reply-To: References: <20220325161428.5068d97e@imladris.surriel.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-1nbVtLEU+9mQSE0QbNkg" User-Agent: Evolution 3.42.4 (3.42.4-1.fc35) MIME-Version: 1.0 Sender: riel@shelob.surriel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-1nbVtLEU+9mQSE0QbNkg Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2022-03-28 at 11:00 +0200, Oscar Salvador wrote: > On Fri, Mar 25, 2022 at 04:14:28PM -0400, Rik van Riel wrote: > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (in= validate_inode_page(page)) > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0poisonret =3D VM_FAULT_NOPAGE; >=20 > What is the effect of returning VM_FAULT_NOPAGE? > I take that we are cool because the pte has been installed and points > to > a new page? (I could not find where that is being done). >=20 It results in us returning to userspace as if the page fault had been handled, resulting in a second fault on the same address. However, now the page is no longer in the page cache, and we can read it in from disk, to a page that is not hardware poisoned, and we can then use that second page without issues. --=20 All Rights Reversed. --=-1nbVtLEU+9mQSE0QbNkg Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAmJDKqEACgkQznnekoTE 3oPaQwgAjpAAjbiuOWl9S6LuGLV7gTR6piiEa7NFUs+d/D8ndjxb0ImtJrHrTF4b 3YO9bln7laVN1+jACN/9FfGQh7YobgviPQ3HJc0bkdxHC1eMrwIEA3n02e1RaZ6Z x5Z14n2+DretUQs8O9CFDR5ioV36yWFpe0VKFlcMik20SDdaE3pbATgHvCnXb8nl NOJcnP95djsEgLMSmSFlBE2EpEF9e1MyYfHF1RVqnNm4KljTEjCouPbiuBU/y/kR 5Wsc8fVZaDSVNKFVM4GCdzBqziwCdYsAaPemPMTO5D9jWrA6f1wudmIKNiO6B1+X KE2keqO/4AXE0JZc/m+f4157Owu0dA== =9sBD -----END PGP SIGNATURE----- --=-1nbVtLEU+9mQSE0QbNkg--