Date: Thu, 15 Aug 2013 17:39:03 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: Michael Tratz <michael@esosoft.com> Cc: Konstantin Belousov <kostikbel@gmail.com>, freebsd-stable@freebsd.org, scottl <scottl@freebsd.org>, Steven Hartland <killing@multiplay.co.uk> Subject: Re: NFS deadlock on 9.2-Beta1 Message-ID: <461392652.9990692.1376602743970.JavaMail.root@uoguelph.ca> In-Reply-To: <F20E755D-EE01-4411-8790-1E2BC7D8CD5D@esosoft.com>
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Michael Tratz wrote: > > On Jul 27, 2013, at 11:25 PM, Konstantin Belousov > <kostikbel@gmail.com> wrote: > > > On Sat, Jul 27, 2013 at 03:13:05PM -0700, Michael Tratz wrote: > >> Let's assume the pid which started the deadlock is 14001 (it will > >> be a different pid when we get the results, because the machine > >> has been restarted) > >> > >> I type: > >> > >> show proc 14001 > >> > >> I get the thread numbers from that output and type: > >> > >> show thread xxxxx > >> > >> for each one. > >> > >> And a trace for each thread with the command? > >> > >> tr xxxx > >> > >> Anything else I should try to get or do? Or is that not the data > >> at all you are looking for? > >> > > Yes, everything else which is listed in the 'debugging deadlocks' > > page > > must be provided, otherwise the deadlock cannot be tracked. > > > > The investigator should be able to see the whole deadlock chain > > (loop) > > to make any useful advance. > > Ok, I have made some excellent progress in debugging the NFS > deadlock. > > Rick! You are genius. :-) You found the right commit r250907 (dated > May 22) is the definitely the problem. > > Here is how I did the testing: One machine received a kernel before > r250907, the second machine received a kernel after r250907. Sure > enough within a few hours the machine with r250907 went into the > usual deadlock state. The machine without that commit kept on > working fine. Then I went back to the latest revision (r253726), but > leaving r250907 out. The machines have been running happy and rock > solid without any deadlocks. I have expanded the testing to 3 > machines now and no reports of any issues. > > I guess now Konstantin has to figure out why that commit is causing > the deadlock. Lovely! :-) I will get that information as soon as > possible. I'm a little behind with normal work load, but I expect to > have the data by Tuesday evening or Wednesday. > Have you been able to pass the debugging info on to Kostik? It would be really nice to get this fixed for FreeBSD9.2. Thanks for your help with this, rick > Thanks again!! > > Michael > >
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