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Date: Fri, 15 Feb 2013 11:22:54 +0000
From: Mike Bristow <mike@urgle.com>
To: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
Subject: Re: dot.core ??
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On Fri, Feb 15, 2013 at 12:01:25PM +0100, Loïc BLOT wrote:
> Hello,
> i have strange problem on one of my FreeBSD 9.1 install.
> The server randomly hard reboots.
> When i look at dmesg i don't find anything, but there is a strange
> entry:
> 
> pid 24931 (dot), uid 0: exited on signal 11 (core dumped)
[snip similar]
 
> There is also a dot.core in /root

"dot" is a program in the graphviz suit, probably.  Someone or something
is running it as root, and it attempts to access memory which it has no
permission to access, so it is killed and a core dump generated.

This memory access is likly to be caused by one of two things:
 1) a bug in dot;
 2) hardware memory corruption 

I suggest you boot memtest86 or similar to see if you can prove the 
hardware fault - especially if you can track down who or what is running 
dot and show that it fails randomly (e.g., if you run it with the same 
input it  does not fail all the time).

Cheers,
Mike

-- 
Mike Bristow                                          mike@urgle.com
                  http://www.urgle.com/~mike/CV/