From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1UYKKi-0007iS-Sz for mharc-grub-devel@gnu.org; Fri, 03 May 2013 14:03:48 -0400 Received: from eggs.gnu.org ([208.118.235.92]:47239) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UYBFu-0004Ox-Dl for grub-devel@gnu.org; Fri, 03 May 2013 04:22:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UYBFr-0001gO-CB for grub-devel@gnu.org; Fri, 03 May 2013 04:22:14 -0400 Received: from dgate10.ts.fujitsu.com ([80.70.172.49]:4199) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UYBFr-0001fn-13 for grub-devel@gnu.org; Fri, 03 May 2013 04:22:11 -0400 DomainKey-Signature: s=s1536a; d=ts.fujitsu.com; c=nofws; q=dns; h=X-SBRSScore:X-IronPort-AV:Received:X-IronPort-AV: Received:Message-ID:Date:From:Organization:User-Agent: MIME-Version:To:CC:Subject:References:In-Reply-To: X-Enigmail-Version:Content-Type:Content-Transfer-Encoding; b=ftvwLePfathzlqNLL10Z7LIGQi5hyRfJ9982HCKngeg49lWc9Te+3/nE udJfIfxAThYBi5aBEjhz7EOjaESa8rnzHFrObX/Qx7JE0emOOMLER4kgc 9v2h2lauq2j9ZKBsvioz1t/pRcu/s4V2pWVpfkqMHXC7H5UQMhR5yizSd l2OIejFox8CcqTBziO3N4gz0HDNN+DvyjR8IeiQkVkAaWSb8jBgdCfDA+ uaVUfxja0kByrTH+hzKdaVFdWfGI9; DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ts.fujitsu.com; i=@ts.fujitsu.com; q=dns/txt; s=s1536b; t=1367569331; x=1399105331; h=message-id:date:from:mime-version:to:cc:subject: references:in-reply-to:content-transfer-encoding; bh=rQn5IRLN/O1S8YZZZ8afytYnsaR6VbdWwAFpKe9ztSs=; b=bV5R+CbF5HK3of5zU7jng3C8+tPYTxhGyJsuNJQoCXP1kU2FSJgJLw9d 3lfUv2a51xTmkpDiU1QGuA9UpTwY/wyfljR33RT1J2HlfazBllP6M3dCu r0x9UJdszP3nqF3Az4V9CRbI9JgQXpCrhVWygwRGaAN1ANMzcBtErt5GE NsjXAg70EHDQWZL0GxCBYxBb9QtUyBvRHo/oFS5BRmH+a0TY1qDsOLP25 N7oG6FZFHxLnE5+mUE4TzRPamtrMS; X-SBRSScore: None X-IronPort-AV: E=Sophos;i="4.87,602,1363129200"; d="scan'208";a="145270514" Received: from unknown (HELO abgdate50u.abg.fsc.net) ([172.25.138.66]) by dgate10u.abg.fsc.net with ESMTP; 03 May 2013 10:21:55 +0200 X-IronPort-AV: E=Sophos;i="4.87,602,1363129200"; d="scan'208";a="9771260" Received: from unknown (HELO cooper.psw.pdbps.fsc.net) ([172.25.253.64]) by abgdate50u.abg.fsc.net with ESMTP; 03 May 2013 10:21:55 +0200 Message-ID: <518373A2.1030300@ts.fujitsu.com> Date: Fri, 03 May 2013 10:21:54 +0200 From: Martin Wilck Organization: Fujitsu Technology Solutions User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130402 Thunderbird/17.0.5 MIME-Version: 1.0 To: Andrey Borzenkov Subject: Re: GRUB and the risk of block list corruption in extX References: <51138645.4050405@ts.fujitsu.com> <20130503090123.3b1f3c4d@opensuse.site> In-Reply-To: <20130503090123.3b1f3c4d@opensuse.site> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.70.172.49 X-Mailman-Approved-At: Fri, 03 May 2013 14:03:47 -0400 Cc: The development of GNU GRUB X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 May 2013 08:22:18 -0000 Andrey, > Here is example how using filesystem blocklists may lead to unbootable > system without any extX corruption involved. > > - user sets up multiboot system with Windows as primary bootloader > - standard technique to add Linux loaders has always been - copy > partition boot sector and "launch" it from Windows loader > - user copies Linux partition boot sector which points to core.imng > absolute disk position > - user updates grub in Linux. core.img is rewritten and its position > changes > - next time user tries to boot Linux (s)he gets blinking cursor > > So *any* third party bootloader that relies on being able to > "chainload" *copy* of boot sector will give you the same issue. I understand. It's generally understood that updating core.img without updating the boot sector is a bad idea. In this particular case updating the boot sector is not enough because the copy needs to be updated, too. The background for my question was a different scenario, with a chainload-capable boot loader in the MBR and secondary boot loaders in partition boot sectors. It is that scenario that the new anaconda installer doesn't support any more, and the major argument from the Fedora devs for this (apart from sparing dev and QA resources) was the warning emitted by GRUB when users try to install using block lists. I am still convinced that the risk of boot loader corruption in that scenario is extremely low. Martin -- Dr. Martin Wilck PRIMERGY System Software Engineer x86 Server Engineering FUJITSU Fujitsu Technology Solutions GmbH Heinz-Nixdorf-Ring 1 33106 Paderborn, Germany Phone: ++49 5251 525 2796 Fax: ++49 5251 525 2820 Email: martin.wilck@ts.fujitsu.com Internet: http://ts.fujitsu.com Company Details: http://ts.fujitsu.com/imprint