topic Re: how to kill a process in Operating System - HP-UX

how to kill a process

Stefano_10 — Tue, 09 Jul 2002 09:32:16 GMT

I have some problem on my server, and i have some processes (as ps, or ll) that don't respond.
I have tried to kill them, also with kill -9 but they are still running.
How can i kill them without restart the server?
Thanks
Stefano

Re: how to kill a process

RAC_1 — Tue, 09 Jul 2002 09:38:36 GMT

If the process is not responding to kill -9 it means it has hunged/zimbie process.

Just a word of caution do not use kill -9 to kill at the first instance. This abruptly kills the process and leave behind memeory segments occupied.

Regards,

Re: how to kill a process

Chris Wilshaw — Tue, 09 Jul 2002 09:39:02 GMT

This can happen as a result of a hardware or software error. The processes are unable to receive and process the kill signal, as they are locked waiting on (for example) disk I/O.

If it's a hardware error on a mirrored disk, pulling the faulty disk from the system can release the processes (trying this on a non-mirorred system is definitely not advisable).

If it's another process that's locking it (waiting as part of an application for example), shutting down the app may solve the issue.

As you have an ll that appears to be hanging, I'd say that a hardware fault is more likely than an application one.

Re: how to kill a process

Nick Wickens — Tue, 09 Jul 2002 10:42:47 GMT

Sounds like your processes have entered the land of the living dead and gone Zombie.

To release them from their enternal torment you will have to reboot I am afraid.

Re: how to kill a process

V. V. Ravi Kumar_1 — Tue, 09 Jul 2002 10:56:15 GMT

hi,

if the process has entered zombie state, u may require to reboot.

regds

Re: how to kill a process

Jeff Schussele — Tue, 09 Jul 2002 11:05:33 GMT

Hi Stefano,

If the process is blocked & waiting on I/O, it will not catch the kill signal. A tar command that's hung can do this. Sometimes resetting (power cycle) the tape drive can free the process.
If the PID has gone zombie, you could determine it's parent & if that's not a vital process you might try to stop or kill the parent - the zombie child could go with it. But I'd caution you to make SURE of what the parent process is - i.e. do not kill PID 1.

HTH,
Jeff

Re: how to kill a process

Stefano_10 — Tue, 09 Jul 2002 11:16:39 GMT

Probably the cause of problem could be the dvd.
I haven't any problem with tape.
So what process on dvd can give tha same problem that Jeff Schussele
has suggested that can be done from tar?

Stefano

Re: how to kill a process

harry d brown jr — Tue, 09 Jul 2002 11:17:23 GMT

If a process doesn't die with a kill -9, and you followed some of the other adice posted, then your only options are:

Ignore it

or

reboot

live free or die
harry

Re: how to kill a process

harry d brown jr — Tue, 09 Jul 2002 11:25:25 GMT

If you have "lsof" you can determine what files the process has open.

find lsof here:

http://hpux.cs.utah.edu/hppd/hpux/Sysadmin/lsof-4.61/

live free or die
harry

Re: how to kill a process

David Totsch — Wed, 10 Jul 2002 02:42:17 GMT

Stefano:

Any process that has a priority less-than or equal to PZERO (see /usr/include/sys/param.h) is not signalable. Let's say you are trying to kill ll(1). There is a good chance it is reading inodes at a priority of PINOD (which is less than PZERO).

Always move from weakest to strongest kills (SIGHUP, SIGINT, SIGQUIT, ...), and use the names. My personal favorite is SIGABRT (just like -9 [aka SIGKILL], it does not give the process a chance to clean up outstanding I/O, shared memory segments, message queues, etc), but it will also generate a core file so that you have a chance to figure out what the process was up to when you felt the need to exert SuperUser powers. In any instance, SIGABRT and SIGKILL are last resorts (and only a reboot will remove what they won't).

BTW: don't worry about memory pages -- the paging algorighm will page them out if memory demands are up and the pages have not been used.

-dlt-