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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 C5800C433E1 for ; Mon, 29 Jun 2020 20:46:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A73FA20663 for ; Mon, 29 Jun 2020 20:46:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="ZiiGvlHC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731629AbgF2Uqg (ORCPT ); Mon, 29 Jun 2020 16:46:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43382 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731552AbgF2TNx (ORCPT ); Mon, 29 Jun 2020 15:13:53 -0400 Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64B8DC08EA4B; Sun, 28 Jun 2020 22:48:06 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 49wGjw1lCLz9sRk; Mon, 29 Jun 2020 15:48:03 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1593409684; bh=/YQUWPTNF1yfjssmjTfskL+aXMkfJR2ADKApusEzfaA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=ZiiGvlHCBnvAF3APkTommNfdvQmDkuYoZMa+llNNHmj31m9lhBnJPy19xfNxjMJiI LOEHaJ8xq26BiOKskUPmfOW4WUU+T79cfWSyDx7RdzCKZJzLLkNz4Oq9G8fr8h9PHV PpMSd3Xc/PQdrP1409zgma9HkuMVo4knpGsQy4+X88UPXbLERDNgC1cb6A2fF7WI5P WiWe7WtJ2hrelBssuoZAIEukoh8LAXk/XNOtW0D20iY0LEcnXYlflR65DabbSdQuIL Gj9HDWDpu1Zwa3R6DkW58ykovlV/uoJL3w1+hw4OyzGz778jSZTfL6rFVsmmhSmNAX mvOcCg0ljaiLQ== From: Michael Ellerman To: Kees Cook Cc: Shuah Khan , Naresh Kamboju , Petr Mladek , Joe Lawrence , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests/lkdtm: Use "comm" instead of "diff" for dmesg In-Reply-To: <202006270849.7190A26@keescook> References: <202006261358.3E8AA623A9@keescook> <87k0zsbubg.fsf@mpe.ellerman.id.au> <202006270849.7190A26@keescook> Date: Mon, 29 Jun 2020 15:50:18 +1000 Message-ID: <87lfk68lph.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Kees Cook writes: > On Sat, Jun 27, 2020 at 09:51:31PM +1000, Michael Ellerman wrote: >> Kees Cook writes: >> > Instead of full GNU diff (which smaller boot environments may not have), >> > use "comm" which is more available. >> >> Although using "comm" requires CONFIG_PRINTK_TIME=y doesn't it? > > No, it doesn't seem to. "comm" doesn't carry about the line prefixes. > AIUI, the only reason for a mention of "sort" is because of how "comm" > does its line pairing. i.e. as soon as it goes out of sync, it starts > accounting for the disjunction between files. But that's exactly what we > want it doing, and the prefix doesn't matter. OK, if it works. cheers