Trouble killing processes in Sy

Bob Toxen bob at cloud9.UUCP
Fri May 6 11:06:31 AEST 1988


In article <13282 at brl-adm.ARPA>, rbj at icst-cmr.arpa (Root Boy Jim) writes:
> Technically, no. Zombies are already dead.
> Killing a zombie has no effect...

Correct.  Zombies merely hold the PID until their parents do a wait()
for them or until their respective parents die causing them to be
inherited by init() (PID 1).  They need to wait for the wait() so that
the exit() status can be returned to the parent's wait().

> I believe that killing a process merely sets a bit in its signal mask, which
> is not looked at until the affected process is rescheduled. Of course, if
> the target process has higher priority and is otherwise ready to run, it
> should preempt the killing process, no?

Correct.  Thus sending multiple signals to a process hung in a system call
or otherwise not getting cycles doesn't do anything.

> 	(Root Boy) Jim Cottrell	<rbj at icst-cmr.arpa>
> 	National Bureau of Standards
-- 

Bob Toxen	{ucbvax!ihnp4,harvard,cloud9!es}!anvil!cavu!bob
Stratus Computer, Marlboro, MA
Pilot to Copilot: What's a mountain goat doing way up here in a cloud bank?



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