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From: Peter Grehan <grehan@freebsd.org>
To: "Niels S. Eliasen" <nse@delfi-konsult.com>
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Date: Fri, 16 Jan 2009 08:00:37 +1000 (EST)
Cc: freebsd-ppc@freebsd.org
Subject: Re: panic in stwu ??
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Hi Niels,

>>> [thread pid 9 tid 100034 ]
>>> Stopped at      0x100444::       stwu r31, r1, -0xb0

 It looks like a stack overflow :( This instruction is bumping
the stack and storing a value into it, and the stack pointer
is probably hitting a guard page.

 These aren't handled very well, other than dropping directly
into the debugger without any message.

 A possible workaround is to bump up the number of pages
allocated for kernel stacks. Drop this into your config file:

options 	KSTACK_MAX_PAGES=5

(the default is 4, and keep going up 'til no overflows are seen).

later,

Peter.