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 80AABCCA479 for ; Fri, 1 Jul 2022 09:16:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1BCB06B0074; Fri, 1 Jul 2022 05:16:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 143696B0075; Fri, 1 Jul 2022 05:16:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F27266B0078; Fri, 1 Jul 2022 05:16:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id E01416B0074 for ; Fri, 1 Jul 2022 05:16:56 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 9D500F04 for ; Fri, 1 Jul 2022 09:16:56 +0000 (UTC) X-FDA: 79637976432.11.12728E5 Received: from smtp2.axis.com (smtp2.axis.com [195.60.68.18]) by imf25.hostedemail.com (Postfix) with ESMTP id 8425DA002D for ; Fri, 1 Jul 2022 09:16:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1656667016; x=1688203016; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=yLWxJPfnToMyz/XrFhdVClGvwJBpxKEAR/Sl0m5JrbU=; b=GL6TSPFB++kfws+rJ2r/j5J837oxq4MmilCAtWCjaNeku26h2W7b8vEL 60pF0TGElggwD+eZMC2tOckfVKaQEHIWOVhCHSOEYPjSfWQgCjhrkIlij b8bllNt6QA2dbrCHQjoDE7DVWf95fuLCsG+cEJSYSQp2df1OaBYr4H2Sq f+nGUidyCEfYx1Kf7ABwRO6j64TL1iayaKYgjpuLlWVVwf2nC8oshBa1a Q3WR+rNvJrwIvDRoEqwQlszaK6hgmrlWjU8uKbQGbaOOPFJ/ntzEljXbt 3cmlnHD8wg+ZsdYzJHLjQPt0Lrsyx5eKlDvtEUkCVVVF6/jY7unZV+EcT Q==; Date: Fri, 1 Jul 2022 11:16:53 +0200 From: Vincent Whitchurch To: David Gow CC: Andrey Konovalov , Dmitry Vyukov , Johannes Berg , Patricia Alfonso , Jeff Dike , Richard Weinberger , "anton.ivanov@cambridgegreys.com" , Brendan Higgins , Andrew Morton , Andrey Ryabinin , kasan-dev , "linux-um@lists.infradead.org" , LKML , Daniel Latypov , "linux-mm@kvack.org" , "kunit-dev@googlegroups.com" Subject: Re: [PATCH v4 2/2] UML: add support for KASAN under x86_64 Message-ID: <20220701091653.GA7009@axis.com> References: <20220630080834.2742777-1-davidgow@google.com> <20220630080834.2742777-2-davidgow@google.com> <20220630125434.GA20153@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656667016; a=rsa-sha256; cv=none; b=d4ObIBjPCnV4zkwbmC/eYR5yrBmrMLqVgnTw/2d/boJrISHQA/aHGFjC+hEsgeqQyrkvCl GAbENZI0IJ7Tbd0CPv471H4fXfFQDtF1P3NUYc3hFUpDJk8XIfmC/qfMWZ1cgWYtAz1hhY vT4yOmJ6OUWpweBXksTuclG+jzenJQo= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=axis.com header.s=axis-central1 header.b=GL6TSPFB; dmarc=pass (policy=none) header.from=axis.com; spf=pass (imf25.hostedemail.com: domain of Vincent.Whitchurch@axis.com designates 195.60.68.18 as permitted sender) smtp.mailfrom=Vincent.Whitchurch@axis.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656667016; h=from:from:sender: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:dkim-signature; bh=yLWxJPfnToMyz/XrFhdVClGvwJBpxKEAR/Sl0m5JrbU=; b=leU1ARvpc5h+LneEBRx9fg0vpMb4YRmkQZ/Q8EZhYXn2Pfdvce2oNIJAtVpGatCdF/9vKL Snu3Qsq2JJzfpIyEtfgunrq1nMvmFTjKQepU+Gk9FFzkzQGZxhKKQjgKOkHEiRkWm5afy9 BcCy/rNhVdefIO0H3mApQKsZf9r2piY= X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 8425DA002D Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=axis.com header.s=axis-central1 header.b=GL6TSPFB; dmarc=pass (policy=none) header.from=axis.com; spf=pass (imf25.hostedemail.com: domain of Vincent.Whitchurch@axis.com designates 195.60.68.18 as permitted sender) smtp.mailfrom=Vincent.Whitchurch@axis.com X-Rspam-User: X-Stat-Signature: cfuu9y3txd7nwbdce49cq6btu7bcdykp X-HE-Tag: 1656667015-8620 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 Fri, Jul 01, 2022 at 11:08:27AM +0200, David Gow wrote: > On Thu, Jun 30, 2022 at 9:29 PM Andrey Konovalov wrote: > > Stack trace collection code might trigger KASAN splats when walking > > stack frames, but this can be resolved by using unchecked accesses. > > The main reason to disable instrumentation here is for performance > > reasons, see the upcoming patch for arm64 [1] for some details. > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/commit/?id=802b91118d11 > > Ah -- that does it! Using READ_ONCE_NOCHECK() in dump_trace() gets rid > of the nasty recursive KASAN failures we were getting in the tests. > > I'll send out v5 with those files instrumented again. Hmm, do we really want that? In the patch Andrey linked to above he removed the READ_ONCE_NOCHECK() and added the KASAN_SANITIZE on the corresponding files for arm64, just like it's already the case in this patch for UML.