kernel panic

Joe Talbott josepht at
Sun May 13 16:44:54 PDT 2007

On Sun, May 13, 2007 at 12:34:35AM -0700, Matthew Dillon wrote:
> :This is a laptop that has been power cycled at least a hundred times
> :since that took place so it seems to me there's no way it was coming
> :from memory.  When my re(4) troubles were happening I had hw.physmem
> :set to 256M to get manageable coredumps.  After my troubles were
> :resolved I removed that entry from my loader.conf.  So this time my
> :dump consisted of 1.5GB as did several re(4) related coredumps prior
> :to my setting hw.physmem.  I assume that the swap space isn't zero'd
> :or otherwise initialized prior to a page being written to it.  I also
> :assume that a coredump is written sparsely to disk so old data could
> :remain across coredumps.  I guess I'll read the code and see if I can
> :learn a bit more rather than making assumptions.
> :
> :Joe
>     It may be worth adding a DELAY in re_stop(), but it will take a
>     while to determine whether it does any good if we can't reproduce
>     the failure consistently.

I made this change and shortly got another hang.  I was in X messing
around with a vkernel and was typing away when everything froze.  I
waited a bit after trying CTRL-ALT-ESC, CTRL-ALT-BKSP, CTRL-ALT-DEL,
and anything else I could think of, but the machine was frozen.  So I
held the power button down for 5s or so and rebooted.  After checking
my filesystems, what do you know another coredump was found and it is
the same as last time.  I am positive that I'm not looking at the
wrong vmcore.  I am inclined to believe that no coredump was ever
written to my swap partition or perhaps only a part of a coredump was
written before I power cycled the laptop.  I'm going to try to trigger
this running from the system console versus in X and see if I can get
into the debugger.  


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