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 picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 115ACC46CA1 for ; Mon, 18 Sep 2023 09:24:43 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id 8827B3CE4D5 for ; Mon, 18 Sep 2023 11:24:41 +0200 (CEST) Received: from in-2.smtp.seeweb.it (in-2.smtp.seeweb.it [217.194.8.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 5D5943CAA0F for ; Mon, 18 Sep 2023 11:24:31 +0200 (CEST) Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-2.smtp.seeweb.it (Postfix) with ESMTPS id BF5B560B2D8 for ; Mon, 18 Sep 2023 11:24:30 +0200 (CEST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 4CAC21F892; Mon, 18 Sep 2023 09:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1695029070; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZPp/Fjd7bD8yNQ7DUsIEbnpxuFRqB6rqdQAwf4ejX+U=; b=O53o1JlcUJaQgzPllbrq2rg1CPv0oNGHss6T9nn/uiyK4OPSduYSIsEhxGo8PWa3C7/Ujp SRIWN/FHDJ+3I7wDyqXdUgoImFOeyS4hEELp0V0i1ELfq1qERi1NT+NhXWrja/dDCLeVZE rjGyBP3oTZSpNx8BqHTy8KmB+iVh/uA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1695029070; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZPp/Fjd7bD8yNQ7DUsIEbnpxuFRqB6rqdQAwf4ejX+U=; b=r0WA8pMTUfzdKdj3+2mqUri5xyPKVVq/XBnmou4i+hlwScwK7QioPF3xinhRKnil4jg0Wj +tx69J3usGkgm0BQ== Received: from g78 (rpalethorpe.tcp.ovpn1.nue.suse.de [10.163.17.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id E59802C142; Mon, 18 Sep 2023 09:24:29 +0000 (UTC) References: <20230808035641.364676-2-iwienand@redhat.com> <87il8xhr05.fsf@suse.de> <65af05ae-bfd1-8153-4662-1bf61be855f3@suse.cz> <845ca8fe-1ae2-13ba-c9e0-a53cf953c0ff@suse.cz> <87r0n2gip5.fsf@suse.de> <87msxpgmf4.fsf@suse.de> User-agent: mu4e 1.10.7; emacs 29.1 From: Richard Palethorpe To: Ian Wienand Date: Mon, 18 Sep 2023 09:24:47 +0100 Organization: Linux Private Site In-reply-to: Message-ID: <87edivhm0i.fsf@suse.de> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 1.0.1 at in-2.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH v2] kernel/device-drivers/zram/zram01.sh : don't fill from /dev/zero X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: rpalethorpe@suse.de Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hello, Ian Wienand writes: > On Thu, Sep 14, 2023 at 08:37:46AM +0100, Richard Palethorpe wrote: >> We don't want to remove coverage of ZRAM_SAME! A bug in ZRAM_SAME is a >> potential expoit or data-corruption. >> >> If you want to change the test you have to show where ZRAM_SAME is being >> covered instead. > > The patch v2 has always had the comment and intent > > + # To make sure we are actually testing both the same-page and > + # compression paths, we first pad with zeros but then fill > + # with a compressible series of alternatiting 0x00 and 0xFF. > + # This should assure we stress the compression path and can > + # calculate the compression level reliabily. > > I believe this tests both paths, and in a more rigorous manner than the > extant test. > > -i I did miss that, however it's actually more rigorous (read "complete") to test these things seperately. Or even better to test them seperately then together. Because if only writing out same-page's and a single page with some meta-data in results in a bug, then your method would not find that. You're still swapping one type of coverage for another. So I'm still in favor of accepting Petr's original patch and of course I would welcome what you are proposing as additional coverage. -- Thank you, Richard. -- Mailing list info: https://lists.linux.it/listinfo/ltp