Modifying a unix process table on the fly
Root Boy Jim
rbj at uunet.UU.NET
Sat Jan 19 11:48:41 AEST 1991
In article <5962 at rtech.Ingres.COM> dan at squid.ingres.com (Dan Dick "Squid Mgr") writes:
>We have a process that is hung waiting for a device driver that will never
>respond. Therefore, that process cannot die--even with a kill -9 <PID>.
>Does anybody have experience flipping the DISK-WAIT flag so the process can
>think it is ok to die gracefully?
I have always thought that setting the "Wait Channel" to the address
of the lightning bolt (lbolt) would be a nice way to either
(1) unwedge a process, or (2) crash the system.
I would think it would depend on the particular type of hang involved.
I used to work with a guy who wrote a "user level sceduler" by
writing into the systems proc tables. This was for a government
procurement to make the benchmarking suites run faster. We were
supposed to tune their kernel and we couldn't get them to put the
stuff in their kernel, so it had to be done as a user process.
--
Root Boy Jim Cottrell <rbj at uunet.uu.net>
Close the gap of the dark year in between
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