My original message is at the bottom.
I had many responses, most of which said a reboot was the only solution, and
two that offered different solutions.
First, almost everyone pointed out what I had forgotten, a parent PID of '1'
would indicate the process is a zombie, which makes sense in this case since
the child porcess in question was probably running a CGI script which in
turn forked and ran a sub-process. The script is old and upon examination
does not wait for its child to exit, but rathers depends on the OS to clean
things up when it exits. This does happen in every case up except for this
incident.
Second, a lot of the responses said the primary cause is a process that is
waiting in the kernel for an I/O signal, which will never come. This
appears to be exactly the case. The almost universal solution was a reboot.
Here is a quote from one of the responses offering solutions other than
rebooting:
"When I attended the Sun SA287 class, this very question came up. The
instructor
replied, If a kill -9 will not delete the process, you can kill the
process by
entering the /proc directory and manually rm'ing the process id."
I plan on trying this the next time I see this, (hopefully never, but....).
It was also suggested that starting up a debugger as root and then
attatching to the process might, and this was a slim chance, enable one to
send the signal being waited for, or maybe at least stopping it.
Thank you to all who responded. (And I hope this helps the next person to
be stuck with this. :-) )
Jim.
> -----Original Message-----
>
> I would have thought this would be covered in the archives or FAQ, but it
> wasn't, at least not in general terms.
>
> I just had to reboot a server because of an un-killable process. The
> process appeared to be a child Apache process, but the parent PID was '1'.
> A kill of any sort, including -9, didn't phaze it. I didn't think of a
> kill -15.
>
> Is there anyway short of rebooting to kill one of these things?
> What causes an un-killable process in the first place?
>
> Thanks!
>
> jim
>
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