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 4E468C433EF for ; Tue, 14 Dec 2021 17:01:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CE66F6B0071; Tue, 14 Dec 2021 12:01:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C960F6B0073; Tue, 14 Dec 2021 12:01:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B5EF06B0074; Tue, 14 Dec 2021 12:01:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0156.hostedemail.com [216.40.44.156]) by kanga.kvack.org (Postfix) with ESMTP id A8A1A6B0071 for ; Tue, 14 Dec 2021 12:01:45 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 70D858849D for ; Tue, 14 Dec 2021 17:01:35 +0000 (UTC) X-FDA: 78917016150.25.505DEFC Received: from mail-qk1-f179.google.com (mail-qk1-f179.google.com [209.85.222.179]) by imf10.hostedemail.com (Postfix) with ESMTP id 72CA6C0043 for ; Tue, 14 Dec 2021 17:01:15 +0000 (UTC) Received: by mail-qk1-f179.google.com with SMTP id l25so8044167qkl.5 for ; Tue, 14 Dec 2021 09:01:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=K6SwQ7kN/dDw+w0mSseLUAWkx7P46fy2j21+TDwHRGQ=; b=geSylfNXtOBB5MFpassheNNfvCZZL8x1Ti8xIAp8L7G+Cs8a5Uj4HqJbNfYU6qm2jq 5vCr00Av2R22T5+ybKQMT2+DZIxGWKFkQPujityyd2ZcHjzGLSmZXGo4csyMxvAC31tt r19YWVeLJAE3LtK3E10d3I8Cg6I3F0OUiBXC2p2qtLaNq01HQDDzS0q1Yc8J+hXL6ntJ ldppbrkbhz0x/CRAZ4Wpn8ilCgchJTxl31qpycWOVvObIakvDqz6ykJdTPnAGp23M80v P98OetMrefut5qXrSfttToSSXdlZ5LSl/frMmQG7fnFg82aloqsDJaVG5IB3hfAIiM71 8Bpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=K6SwQ7kN/dDw+w0mSseLUAWkx7P46fy2j21+TDwHRGQ=; b=kSm5yNJzbwfA4X3oztufWoSU2E+mouzg9PtcPBwYNboJhxWBTEocdsGZEsxKnoB1q6 UxFvrZc4ieLS3B3y1XDLeInVcE8MB03ybkXQxvEOrfYNu3KBEKLP2DIqBWjhdpzOQnbP WwVk1Uibg9sepGJnxIQzQLhrSErZUIMFNeDGABokrjx7xKNVM+cBbg4vrMbdXA9ifT4B Hg9VwKtZfLju99wA6ll0dzJjJ4Bv/B0bMRAJOuhqGzU08XtTdUd3VdvdjT+nEvM/t/3f XPZiU8ILDd/FM/+JoYjzUl4gxP4y7EIg57x4XCYGvQJrXBAEhKyl2xcIRcQ3enUs57oh Enlw== X-Gm-Message-State: AOAM530yfT2tyXY71os7541B5aYqNxGdm6IDBHurF4+zSm2JyafF5q/b tbmv2zForKFp8L7sULSs/bN9DYMdw+upxo5uaChm4g== X-Google-Smtp-Source: ABdhPJxFv9ZFHoPXaaC/osRtc8a0bS2qHEXsr2DcKiYvm2pnK++TLb5sKoemfjwrn9CS2MWsFW6/45fBFq2DIZSvFzI= X-Received: by 2002:a05:620a:2848:: with SMTP id h8mr5214238qkp.610.1639501277945; Tue, 14 Dec 2021 09:01:17 -0800 (PST) MIME-Version: 1.0 References: <20211214162050.660953-1-glider@google.com> <20211214162050.660953-42-glider@google.com> In-Reply-To: From: Alexander Potapenko Date: Tue, 14 Dec 2021 18:00:41 +0100 Message-ID: Subject: Re: [PATCH 41/43] security: kmsan: fix interoperability with auto-initialization To: Greg Kroah-Hartman Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 72CA6C0043 X-Stat-Signature: gxkppzg654y1mcazmh9mreqgusmydryp Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=geSylfNX; spf=pass (imf10.hostedemail.com: domain of glider@google.com designates 209.85.222.179 as permitted sender) smtp.mailfrom=glider@google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1639501275-414564 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 Tue, Dec 14, 2021 at 5:38 PM Greg Kroah-Hartman wrote: > > > @@ -124,6 +125,7 @@ choice > > config INIT_STACK_ALL_ZERO > > bool "zero-init everything (strongest and safest)" > > depends on CC_HAS_AUTO_VAR_INIT_ZERO > > + depends on !KMSAN > > So this means KMSAN is a developer debugging feature only and should > never be turned on on a real device/server that has users? 100% correct. KMSAN is way slower than KASAN, it also eats 2/3 of your memory to store the metadata. I thought it was sort of self-evident, but I can surely mention this explicitly in the cover letter.