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 EC213C433F5 for ; Mon, 6 Dec 2021 21:08:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F18746B0085; Mon, 6 Dec 2021 16:08:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E9F8A6B0087; Mon, 6 Dec 2021 16:08:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D40256B0088; Mon, 6 Dec 2021 16:08:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0043.hostedemail.com [216.40.44.43]) by kanga.kvack.org (Postfix) with ESMTP id C1CE46B0085 for ; Mon, 6 Dec 2021 16:08:26 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8DAE81815CC0E for ; Mon, 6 Dec 2021 21:08:16 +0000 (UTC) X-FDA: 78888607392.23.E357CAE Received: from mail-il1-f171.google.com (mail-il1-f171.google.com [209.85.166.171]) by imf29.hostedemail.com (Postfix) with ESMTP id 2B6FF9000247 for ; Mon, 6 Dec 2021 21:08:16 +0000 (UTC) Received: by mail-il1-f171.google.com with SMTP id s6so6140741ild.9 for ; Mon, 06 Dec 2021 13:08:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=MIBC6uZiK3qw8zipA5+LmK5bPUNLM9r4EQ+nUCy7/lw=; b=INmG1BwTmj3+cLahz2Xuw59SFmU2O7hk4q8DxKCvFawc/lbK2rXo6XlOH03eaPjJ4r BkDoSUJcr+fAOGsor2ZV2CbxjFT3X26JcoCou1+1uSpvNOQEQ1e9KooYEIyeKSD2XVgA /DlU+Uz1n/6XV5VuQ7ZHCzAtjDtYyuiyQQDVnPKbEYxP2rgLtMFPbjnu/j7LPlk/OG1D etunBOsfbZvM5gNAGTw7RasfrrC1MgYuR9BGvNrAoE6DqXpY9QGxYzamtjR/gWj6g9bM FY/UaLBaBdKlmP1HU9jx4XOn9nCuSoaguRiF23ow+qany12dOU7p+osWvOTIcqxNz3vc fboQ== 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=MIBC6uZiK3qw8zipA5+LmK5bPUNLM9r4EQ+nUCy7/lw=; b=7XCX9PpxRyRI95/TWW9838+2Ah6A2xDnIs4axZRacxadd8/WT7+YU5X1utcutSK3nV ArFQOSoBfCoHZNgS3bU+SZCQ56FbuzUrIXr8ZMwu1GuwmvH+TypljC9p9dPhttoIDQRX oPhYah4neOsdBpoRuKazvCYNNcTuq8qytcf9zH2RBgNGqtdZXF2jsdRuhoxnDEipy+3V 0ldv2zfDuDVlA8SUBScx8YJlIV+eqQpqjg9b76Tg0gfZNxyZzF+yBjymGAfxssPbPRrc dZ64JD3FSSzBp2sagT/9MklTAXb/0kcAnARfHCK83lIACFKkDOAJhxPK8DMuMT7iX9P7 0gDA== X-Gm-Message-State: AOAM5303wHGsPrQ9Cazim5q1v2dKY+314WbZ7SSq4FblktH4dCIAtKEC N3KyLeJRMvDiojZ1KwVWcT/lkBKdfKlh9ohXlis= X-Google-Smtp-Source: ABdhPJxQCtZ33FUXaFDtaku5StVr7BWXLnYl6zjud+9nZ/VlZL4qwxyr7DiBkwVXyvwGbAcwzOLBk6e4yGawn8E9nBM= X-Received: by 2002:a05:6e02:1605:: with SMTP id t5mr38923380ilu.233.1638824895522; Mon, 06 Dec 2021 13:08:15 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Andrey Konovalov Date: Mon, 6 Dec 2021 22:08:04 +0100 Message-ID: Subject: Re: [PATCH 20/31] kasan, vmalloc: reset tags in vmalloc functions To: Marco Elver Cc: andrey.konovalov@linux.dev, Alexander Potapenko , Vincenzo Frascino , Catalin Marinas , Peter Collingbourne , Dmitry Vyukov , kasan-dev , Andrew Morton , Linux Memory Management List , Will Deacon , Linux ARM , Evgenii Stepanov , LKML , Andrey Konovalov Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 2B6FF9000247 X-Stat-Signature: hni6m8p9tdqgpracszn9n9ee75t565wn Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=INmG1BwT; spf=pass (imf29.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.166.171 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-HE-Tag: 1638824896-514628 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 Thu, Dec 2, 2021 at 3:17 PM Marco Elver wrote: > > On Tue, Nov 30, 2021 at 11:07PM +0100, andrey.konovalov@linux.dev wrote: > > From: Andrey Konovalov > > > > In preparation for adding vmalloc support to SW/HW_TAGS KASAN, > > reset pointer tags in functions that use pointer values in > > range checks. > > > > vread() is a special case here. Resetting the pointer tag in its > > prologue could technically lead to missing bad accesses to virtual > > mappings in its implementation. However, vread() doesn't access the > > virtual mappings cirectly. Instead, it recovers the physical address > > s/cirectly/directly/ > > But this paragraph is a little confusing, because first you point out > that vread() might miss bad accesses, but then say that it does checked > accesses. I think to avoid confusing the reader, maybe just say that > vread() is checked, but hypothetically, should its implementation change > to directly access addr, invalid accesses might be missed. > > Did I get this right? Or am I still confused? No, you got it right. Will reword in v2. Thanks!