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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23A3AC38A2A for ; Fri, 8 May 2020 07:30:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECBBD20643 for ; Fri, 8 May 2020 07:30:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="hZKbAYW3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726797AbgEHHaQ (ORCPT ); Fri, 8 May 2020 03:30:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726049AbgEHHaP (ORCPT ); Fri, 8 May 2020 03:30:15 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A6D9C05BD09 for ; Fri, 8 May 2020 00:30:15 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id 145so487343pfw.13 for ; Fri, 08 May 2020 00:30:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=cqpyyb+XnLoj16wQZlLdWBVriL281dJ6+6/0xxtkFF0=; b=hZKbAYW33xb+xdQ8lBH9aT3oQXgi4QwV4iyIiZZxmjGdeY2HuZSMuK1Tv0vl5FXkoD lpolHB5qaTBvXWNFPcAWHh/cUtiXAyBsQO3w8th6r0E8mu6tSopQy2Qfp+qqBZu01LRn nyb7OqEjzsaHtT5Dn1N4KbgZ/UmchV1hf/rl0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=cqpyyb+XnLoj16wQZlLdWBVriL281dJ6+6/0xxtkFF0=; b=aN0MbyYlKDsxw15cqg9xEsyYq5SHkPYBZ3K68f9RWl8VMyiB0Lx5lXYo736/tGpa9w uiNXrCWvJOTWAP12gf9/HJ/6NAi8nRIjULuWDrIQY+XpyaoPMdNiE+vCdPwd77Ru564N zS6qknJiYT/fG/iwvbBjQBd1Bn1a9W1WvxL7Fkzt/YO81b259k9TEJBtsjZL0F4BnhTX Iueqnbay/Nk5Es6+ilKd8xmLJqjTx4Rcwvrqhy1zx7pa4yMRB+Z+uCgxLW336FG1hYa1 tsBpDbJU8Ln6UUYbB9dqCvwaThFGMw6l7433I7zHu+7tKTxSijunnQbVZQvfyC9J1En5 9Iog== X-Gm-Message-State: AGi0PubsqaRMZOA81MJU/WasOXrMeqWnUXNxZI32e6lEyrB83vJ/3N2m tzAlIfBdn1WSLG/BluLIL2LuhA== X-Google-Smtp-Source: APiQypLxKaNbmOsuHu9lpEurBe6lHAKMXWmXDPwAWCdC4ArcRmf7jd0ENIeqyF7Nb5foJhJTNn7u5Q== X-Received: by 2002:a63:5413:: with SMTP id i19mr1095604pgb.213.1588923015051; Fri, 08 May 2020 00:30:15 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id o190sm869295pfb.178.2020.05.08.00.30.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 May 2020 00:30:14 -0700 (PDT) Date: Fri, 8 May 2020 00:30:13 -0700 From: Kees Cook To: Michael Ellerman Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] selftests/lkdtm: Don't clear dmesg when running tests Message-ID: <202005080029.538E27C@keescook> References: <20200508065356.2493343-1-mpe@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200508065356.2493343-1-mpe@ellerman.id.au> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 08, 2020 at 04:53:55PM +1000, Michael Ellerman wrote: > It is Very Rude to clear dmesg in test scripts. That's because the > script may be part of a larger test run, and clearing dmesg > potentially destroys the output of other tests. > > We can avoid using dmesg -c by saving the content of dmesg before the > test, and then using diff to compare that to the dmesg afterward, > producing a log with just the added lines. Sounds good to me! > > Signed-off-by: Michael Ellerman Acked-by: Kees Cook -- Kees Cook