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Date: Thu, 24 Jun 2004 16:06:00 -0400
From: Brian Fundakowski Feldman <green@freebsd.org>
To: Andrew Gallatin <gallatin@cs.duke.edu>
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cc: Claus Guttesen <cguttesen@yahoo.dk>
cc: current@freebsd.org
Subject: Re: unable to make a crashdump
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On Thu, Jun 24, 2004 at 07:58:25AM -0400, Andrew Gallatin wrote:
> 
> Claus Guttesen writes:
>  > Hi.
>  > 
>  > I'm trying to get a crashdump from my kernel when it
>  > panics. I have the following in my kernel:
>  > 
>  > makeoptions     DEBUG=-g
>  > options         DDB, DDB_UNATTENDED
> 
> You may also want to add  DDB_TRACE.  This gets a stack
> trace on console regardless of a crashdump's success.
> You may have to jot it down by hand, but in many cases its enough
> to characterize the panic enough for a meaningful problem report.
> 
> <...>
> 
>  > syncing bugger 3795
>  > 
>  > And then it hangs. Swap is 2 GB, RAM is 1 GB.
>  > 
> 
> 
> Sync'ing on panic nearly always locks my machines up too.
> When I turn this off (sysctl kern.sync_on_panic=0), then
> I reliably get dumps.
> 
> Is anybody able to reliably get dumps with kern.sync_on_panic enabled?
> Maybe it works on SCSI boxes (all of my crashboxes are IDE)...

I don't have SCSI, but it certainly doesn't work for me.  I have no idea
why it's the default when it screws over so many people (and how is it
going to work if the filesystem code panics?)

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green@FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\