Date: Fri, 27 Apr 2007 16:03:19 -0300 From: "Marc G. Fournier" <freebsd@hub.org> To: Kris Kennaway <kris@obsecurity.org>, LI Xin <delphij@delphij.net> Cc: freebsd-stable@freebsd.org, Oleg Derevenetz <oleg@vsi.ru> Subject: Re: How to report bugs (Re: 6.2-STABLE deadlock?) Message-ID: <A5A7F962E5B9C36872977B4D@ganymede.hub.org> In-Reply-To: <20070425035316.GB44054@xor.obsecurity.org> References: <20070313140848.GA89182@steerpike.hanley.stade.co.uk> <20070423025631.GA33256@steerpike.hanley.stade.co.uk> <20070423113912.GE2052@deviant.kiev.zoral.com.ua> <462DDB4D.8080507@delphij.net> <1177442585.462e5919c71f0@webmail.vsi.ru> <462EC294.3040001@delphij.net> <20070425035316.GB44054@xor.obsecurity.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - --On Tuesday, April 24, 2007 23:53:16 -0400 Kris Kennaway <kris@obsecurity.org> wrote: > On Wed, Apr 25, 2007 at 10:53:08AM +0800, LI Xin wrote: >> Hi, Oleg, >> >> Oleg Derevenetz wrote: >> > ??????? LI Xin <delphij@delphij.net>: >> [...] >> >> I'm not very sure if this is specific to one disk controller. Actually >> >> I got some occasional reports about similar hangs on amd64 6.2-RELEASE >> >> (slightly patched version) that most of processes stuck in the 'ufs' >> >> state, under very light load, the box was equipped with amr(4) RAID. >> >> >> >> I was not able to reproduce the problem at my lab, though, it's still >> >> unknown that how to trigger the livelock :-( Still need some >> >> investigate on their production system. >> > >> > I reported simular issue for FreeBSD 6.2 in audit-trail for kern/104406: >> > >> > http://www.freebsd.org/cgi/query-pr.cgi?pr=104406&cat= >> > >> > and there should be a thread related to this. Briefly, I suspects that >> > this is related to nullfs filesystems on my server and when I cvsuped to >> > FreeBSD 6.2- STABLE with Daichi's unionfs-related patches and replaced >> > nullfs-mounted fs with unionfs-mounted (that was done 10.03.07) problem >> > is gone (seems to be so, at least). >> >> Hmm... Seems to be different issues. The problem I have received was a >> pgsql server (no nullfs/unionfs involved), and the hang always happen >> when it is not being heavily loaded (usually in the morning, for >> instance, and there is no special configuration, like scheduled tasks >> which can generate disk load, etc., only the entropy harvesting), so >> this is quite confusing. > > Yes, a large part of the confusion is the unfortunate tendency of > people to do the following: > > <user1> my system hangs/panics/etc > <user2> my system hangs/panics/etc too; it must be the same problem! > > What we really need is for every FreeBSD user who encounters a > hang/panic/etc to avoid jumping to conclusions -- no matter how many > superficial similarities there may seem to you -- and instead go > through the relevant steps described here: > > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kernelde > bug.html > > Until you (or a developer) have analyzed the resulting information, > you cannot definitively determine whether or not your problem is the > same as a given random other problem, and you may just confuse the > issue by making claims of similarity when you are really reporting a > completely separate problem. What about those that don't have the benefit of being able to access the console? :( I've recently started buying servers that have builtin, full remote console (ie. the HP servers), but, for instance, I have one box that I have to consistently reboot ever 3 days due to a 'No Buffer Space Available' ... A thought: how hard would it be to add some method of forcing a system crash, that would dump core, from the command line? Something that, by default, would be disabled, but for remote debugging purposes, one could enable in the kernel and do a 'sysctl kernel.force_core_crash=1' to have it do it? I imagine that having a core to analyze would allow providing more information then nothing at all, no? - ---- Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email . scrappy@hub.org MSN . scrappy@hub.org Yahoo . yscrappy Skype: hub.org ICQ . 7615664 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFGMkj34QvfyHIvDvMRAnIsAJ42loBGh0TkX4mfWSrZrMq2FheBuQCgiu4l B0PCLtLhd9ZiJ4oNLWZ6LT0= =KK9Y -----END PGP SIGNATURE-----
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