when does kill -9 pid not work?

[Gregory N. Bond]

One source of non-interruptable sleeps in live processes is
kernel-based network services. (My experience is with SunOS 3.5
kernels, but I suspect most NFS implemenations would have the same
problems.) 

I have had a number of experiences with processes hanging when things
like lockd or statd or portmap are dead on a machine on the network.
These are things used by the kernel alorithms, so are < PZERO
priority. This morning, suntools on one workstation was frozen because
one process was trying to lock a file, and the local statd was dead.
kill -9 wouldn't kill the process.  When the statd was restarted (a
hairy experience, too!) the process went away and the accumulated
input events were processed by the window system.

These are an indication that the paradigm for NFS in huge kernels is a
bit strained.  Perhaps a mach-like messages-with-kernel-processes
paradigm could avoid this?

Greg.-- 
Gregory Bond, Burdett Buckeridge & Young Ltd, Melbourne, Australia
Internet: gnb at melba.bby.oz.au    non-MX: gnb%melba.bby.oz at uunet.uu.net
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