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From: John Baldwin <jhb@freebsd.org>
To: Ian FREISLICH <ianf@clue.co.za>
Subject: Re: Filesystem wedges caused by r251446
Date: Thu, 11 Jul 2013 09:23:06 -0400
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 (bigwig.baldwin.cx); Thu, 11 Jul 2013 09:23:17 -0400 (EDT)
Cc: Konstantin Belousov <kostikbel@gmail.com>, freebsd-current@freebsd.org
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On Thursday, July 11, 2013 6:54:35 am Ian FREISLICH wrote:
> John Baldwin wrote:
> > On Thursday, July 04, 2013 5:03:29 am Ian FREISLICH wrote:
> > > Konstantin Belousov wrote:
> > > > 
> > > > Care to provide any useful information ?
> > > > 
> > > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-
> > handbook/kerneldebug-deadlocks.html
> > > 
> > > Well, the system doesn't deadlock it's perfectly useable so long
> > > as you don't touch the file that's wedged.  A lot of the time the
> > > userland process is unkillable, but often it is killable.  How do
> > > I get from from the PID to where the FS is stuck in the kernel?
> > 
> > Use kgdb.  'proc <pid>', then 'bt'.
> 
> So, I setup a remote kbgd session, but I still can't figure out how
> to get at the information we need.
> 
> (kgdb) proc 5176
> only supported for core file target
> 
> In the mean time, I'll just force it to make a core dump from ddb.
> However, I can't reacreate the issue while the mirror (gmirror) is
> rebuilding, so we'll have to wait for that to finish.

Sorrry, just run 'sudo kgdb' on the box itself.  You can inspect the running
kernel without having to stop it.

-- 
John Baldwin