Subject: system hang
To: None <port-i386@netbsd.org>
From: Germano Cesari <germano.cesari@tesoro.it>
List: port-i386
Date: 10/25/2002 18:46:48
Hi, just a newbie question:

Im using vmware 2.0.4 that comes among the packages of the NetBSD 1.6 6
CD distribution, I actually didnt have any problem installing linux
emulation and running netscape, acrobat reader or even vmware, but
there's something that really puzzles me...

Im running NetBSD on a PIII 733 with only 128Mb, and IFF I set the total
memory of a vmware virtual machine at > 32Mb, the ENTIRE NetBSD system
would start slooooowing more and more, ignoring any mouse movements,
till a final total system hang (no mouse, no keyb, clock frozen, no hdd
activity, NO REMOTE CONNETCIONS, and so on, you got the point I
guess...), where a power off is the only solution?

just to know, can some1 explain me how is this possible? I mean: that a
process can cause a total system crash? I tought the kernel had control
over every process running, eventually taking care of memory alloc. &
the like, preventing runaways from crashing everything... now, how come
vmware is able to get control over the entire system? has it something
to do with the lkm(s) vmware installs? do they "modify" the kernel in a
way that allows vmware to gain hardware control in a way not usually
possible for other processes? (Ive noted vmware accesses hardware device
independently of NetBSD, "directly" Id say)

if so, would it mean that running vmware (or loading his kernel 
modules) can make the entire system unstable? is it possible to write a
kernel module that modifies the kernel making a total system crash
possible (or even achievable)?

thnx in advance :)

Germano