From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 34F711382C5 for ; Sat, 3 Feb 2018 08:24:11 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 8ACE6E0A7F; Sat, 3 Feb 2018 08:24:04 +0000 (UTC) Received: from blaine.gmane.org (unknown [195.159.176.226]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 0F83CE09F3 for ; Sat, 3 Feb 2018 08:24:03 +0000 (UTC) Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1eht58-00075Z-32 for gentoo-user@lists.gentoo.org; Sat, 03 Feb 2018 09:21:54 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: gentoo-user@lists.gentoo.org From: Nikos Chantziaras Subject: [gentoo-user] Re: Heads Up - glibc-2.27 breaks my system Date: Sat, 3 Feb 2018 10:23:56 +0200 Message-ID: References: <5x7d1x01i1kktTk01x7eRl> <475348c8-d753-88f6-b282-0a90a5b3baa6@gmail.com> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@blaine.gmane.org User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 In-Reply-To: <475348c8-d753-88f6-b282-0a90a5b3baa6@gmail.com> Content-Language: en-US X-Archives-Salt: af7b2a3c-d79a-481d-836a-52526d8ba8cd X-Archives-Hash: 3139c68155b5cee70d5e7767a7fc1cfb On 03/02/18 07:54, Dale wrote: > While on this topic, I have a question about glibc.  I have it set in > make.conf to save the binary packages.  Generally I use it when I need > to go back shortly after a upgrade, usually Firefox or something. > However, this package is different since going back a version isn't a > good idea.  My question tho, what if one does go back a version using > those saved binary packages?  Has anyone ever did it and it work or did > it and it fail miserably? It is perfectly fine to downgrade glibc if you didn't emerge anything that compiled binaries. If you did, you can still downgrade, but then you need to rebuild the packages that you emerged since the glibc upgrade. qlop is your friend here; it lets you find out the dates on which you emerged packages. This whole thing is not actually special to glibc. Other libraries work in a similar manner. You can't just link other software against a new version of the library, then remove the library and replace it with an older one. It might result in breakage. But glibc is used by almost everything, it's not "just a library", it is *the* library, and so it has a special protection to prevent a downgrade. You can bypass that protection and downgrade anyway, but then you need to know what you're doing and how to restore your system correctly. If any sys-devel packages are affected, you might not be able to do it. If only end-user packages are affected which are not used during an emerge, then it's quite safe to downgrade.