From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gnu.wildebeest.org (wildebeest.demon.nl [212.238.236.112]) by sourceware.org (Postfix) with ESMTPS id 4B676393F87A; Wed, 19 May 2021 14:58:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 4B676393F87A Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=klomp.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mark@klomp.org Received: from tarox.wildebeest.org (ip-213-127-36-226.ip.prioritytelecom.net [213.127.36.226]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by gnu.wildebeest.org (Postfix) with ESMTPSA id 1035C302BBED; Wed, 19 May 2021 16:58:41 +0200 (CEST) Received: by tarox.wildebeest.org (Postfix, from userid 1000) id BABC7413CD48; Wed, 19 May 2021 16:58:40 +0200 (CEST) Message-ID: Subject: Re: Storing package metadata in ELF objects From: Mark Wielaard To: Guillem Jover , Luca Boccassi Cc: devel@lists.fedoraproject.org, SystemD Devel , debhelper@packages.debian.org, binutils@sourceware.org, Lennart Poettering , debian-dpkg@lists.debian.org, "elfutils-devel@sourceware.org" , Zbigniew =?UTF-8?Q?J=C4=99drzejewski-Szmek?= Date: Wed, 19 May 2021 16:58:40 +0200 In-Reply-To: References: <2b91ec1654b6c07cca2b5c113df772c85c0dd22c.camel@debian.org> <46a14fa448452ba7c695c7e7eeb4ef9348f5475b.camel@debian.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Evolution 3.28.5 (3.28.5-10.el7) Mime-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: elfutils-devel@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Elfutils-devel mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 May 2021 14:58:43 -0000 Hi Guillem, On Wed, 2021-05-19 at 02:19 +0200, Guillem Jover wrote: > So this is where I guess I'm missing something. To be able to make > sense of the coredumps there are two things that might end up being > relevant, backtraces and source code. systemd-coredump might already > emit a backtrace, and depending on the information provided it might > be more or less useful. If one needs the actual debug symbols there's > already some external querying/fetching required, and if distribution > specific source code is required because many distributions patch > upstream source, then even more querying/fetching will be required. >=20 > Which is why I'm not seeing why this standalone and isolated metadata > would be of much help by itself. As in, the way I see it, either the > information from systemd (w/o the extra metadata) is sufficient to > track down bugs, or that querying/fetching would be needed anyway, at > which point the metadata can be inferred too then? Because without that metadata you cannot easily figure out where/how to get the files needed to properly track down the bugs. But using that metadata you can figure out where the debuginfod server is that can provide all that information for the binaries/core files (or a distro specific method if the distributor doesn't have a debuginfod server yet). > Oh, I was thinking about those mixed environments, full chroots or > stripped down containers, from different vendors, but affecting Debian > installations. What I'm also probably missing here is how does the > metadata help for a third-party that is not expected to track/keep/upload > debug symbols nor source packages into some repository, because otherwise > I'm not seeing how they'd make use of the cores (if they are insufficient > by themselves) to debug issues? I guess my question back would be what > would they do with the metadata if they do not have the debug symbols > nor the sources readily available? Also assuming of course they exercise > good practices such as never reusing the same package-version-arch tuple > for different builds, and similar. :) Different builds will have different build-ids, so they can be kept apart. But even if without the distributor having added debuginfod meta-data and providing a server to fetch the extra symbols, debuginfo, sources, the extra meta-data is useful to administrators. Just seeing that crashes are associated with specific distro/version/packages helps narrow down instabilities. Cheers, Mark