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Date: Sat, 14 Apr 2012 17:02:53 +0200
From: Jeremie Le Hen <jeremie@le-hen.org>
To: Robert Huff <roberthuff@rcn.com>
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Cc: Alexander Best <arundel@freebsd.org>, freebsd-current@freebsd.org,
	Jeremie Le Hen <jeremie@le-hen.org>
Subject: Re: howto debug a complete hard reset
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On Sat, Apr 14, 2012 at 08:59:42AM -0400, Robert Huff wrote:
> 
> >  This is probably a sysctl handler that is causing the reboot.  You can
> >  run this one-liner to spot the culprit (use sh):
> >  
> >      for i in $(sysctl -Na); do sysctl $i >> ~/sysctl.out; sync; done
> >  
> >  Each sysctl will be called in turn and the output is appended to
> >  a file, but the file will forcibly written to the disk before the
> >  next occurence.
> 
> 	Um ... it is my understanding sync(8) does not guarantee
> pending i/o will be written before it returns, but merely requests
> this happen irrespective of when it would normally occur.
> 	An I mistaken?

Honestly I don't know, but I have do admit that the small paragraph in
the BUGS section of the sync(2) manpage is a little bit shivering:

    BUGS
	 The sync() system call may return before the buffers are completely
	 flushed.


Can any enlightened person answer this?

-- 
Jeremie Le Hen

Men are born free and equal.  Later on, they're on their own.
				Jean Yanne