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 28D4AC678D5 for ; Wed, 8 Mar 2023 08:54:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A1AE96B0074; Wed, 8 Mar 2023 03:54:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9A3346B0075; Wed, 8 Mar 2023 03:54:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8456F280002; Wed, 8 Mar 2023 03:54:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 6F72A6B0074 for ; Wed, 8 Mar 2023 03:54:17 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 3864C160899 for ; Wed, 8 Mar 2023 08:54:17 +0000 (UTC) X-FDA: 80545119354.24.8074467 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf01.hostedemail.com (Postfix) with ESMTP id AD5454000F for ; Wed, 8 Mar 2023 08:54:07 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=temperror ("DNS error when getting key") header.d=alien8.de header.s=dkim header.b=Tq5bUtS4; spf=temperror (imf01.hostedemail.com: error in processing during lookup of bp@alien8.de: DNS error) smtp.mailfrom=bp@alien8.de; dmarc=temperror reason="query timed out" header.from=alien8.de (policy=temperror) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 0D24B1EC068F; Wed, 8 Mar 2023 09:54:00 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1678265640; 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:in-reply-to:in-reply-to: references:references; bh=Lx+RtzEAI/Slt9PnACaAiwIIiVncBJt8vf25npLTWIw=; b=Tq5bUtS4Q5K9bX5guN+oxYuAy7F6QgZ2H55hEoG3FMab4FjiaTFTYnjGlWPRxMH3d6tF1U AL+Z5rk8nMkZp9oAb33R9UMNB9T0zBgq1lFONG2kG9ezmNUmdEOv2+WpNqS/oGO6X+ue/B RvMeh/XO2tf5CdetPqmMpOYWWW2TKlA= Date: Wed, 8 Mar 2023 09:53:54 +0100 From: Borislav Petkov To: Rick Edgecombe Cc: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, david@redhat.com, debug@rivosinc.com Subject: Re: [PATCH v7 26/41] mm: Warn on shadow stack memory in wrong vma Message-ID: References: <20230227222957.24501-1-rick.p.edgecombe@intel.com> <20230227222957.24501-27-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230227222957.24501-27-rick.p.edgecombe@intel.com> X-Rspamd-Queue-Id: AD5454000F X-Stat-Signature: uigyyx94wqq3hnrfmnox8ebxb1o6ifp6 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1678265647-721947 X-HE-Meta: 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 NetTsy2x 75JKm6wovPmQgvXPS660nMMdSMf6NAh5eejX4g8HQUOh8h1PS/GPqyRSQ+ohs7fmkkkiwm6KeQUHSybmUf2VpFypPAnFCIUoMe2E+4GTe8ap2mw2RbNSLS3f+zptoYU/TongMJM0I44U+RaFVIUelRgJPLpCml+afOa+btXPtDL3E7KsoCGy2mnJ29FA/RBG4sdMKcddiLQo1+YANU9lFh0gKugTwnHDHaFHBKdLFdIike1edpeGRJ/scTHi0ptxYyFU/1Axy43HsAcFPZEyCjEY7aMQX69RAY/Fovf6w5pV6HfOt1eCc0QKbT0QQNtcxFlmtKcU+Q3UFqqO2vCWBSzgXpzCpfx81HzIKFwHs7vqN0iIiyneR10yLQbtqKXx8mLmPL9P4wC0Qd3qZTx1fweXF9Vg/YhtkZAmZ 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: On Mon, Feb 27, 2023 at 02:29:42PM -0800, Rick Edgecombe wrote: > The x86 Control-flow Enforcement Technology (CET) feature includes a new > type of memory called shadow stack. This shadow stack memory has some > unusual properties, which requires some core mm changes to function > properly. > > One sharp edge is that PTEs that are both Write=0 and Dirty=1 are > treated as shadow by the CPU, but this combination used to be created by > the kernel on x86. Previous patches have changed the kernel to now avoid > creating these PTEs unless they are for shadow stack memory. In case any > missed corners of the kernel are still creating PTEs like this for > non-shadow stack memory, and to catch any re-introductions of the logic, > warn if any shadow stack PTEs (Write=0, Dirty=1) are found in non-shadow > stack VMAs when they are being zapped. This won't catch transient cases > but should have decent coverage. It will be compiled out when shadow > stack is not configured. > > In order to check if a pte is shadow stack in core mm code, add two arch s/pte/PTE/ -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette