Re: Hard kill a process?

x0054 wrote in <Xns97D2EEAEA1F1Cx0054indexcom@xxxxxxxxxxxxxx> on Tue, May 30
2006 02:32:

Just wondering, if you can point me to an article that discusses this
topic more I would be grateful. It sounds very interesting to me.


Sure thing -- this is just the first hit back from Google:

,----[ http://linuxgazette.net/issue83/tag/6.html Quote ]
| A process which ends up in "D" state for any measurable length of time is
| trapped in the midst of a system call (usually an I/O operation on a
| device --- thus the initial in the ps output).
|
| Such a process cannot be killed --- it would risk leaving the kernel in an
| inconsistent state, leading to a panic. In general you can consider this
| to be a bug in the device driver that the process is accessing.
|
| Once case that I can't consider to be a Linux bug occurs when one is
| attempting to access a hard mounted NFS exported share without the intr
| (mount( 8)) flag. If the NFS server (or the network connection thereto)
| becomes unavailable all processes that try to access any part of that
| share will be set into D state. (Use intr or soft mount options on NFS to
| avoid all that). I might consider that to be a design bug in the NFS
| protocol --- but that might be contentious. That particular NFS behavior
| can actually be a feature in some cases; I think it should NOT be the
| default, though.
|
| When it comes to scsi and similarly local device drivers --- I would
| report cases of "D" state as bugs (after due diligence of checking for
| prior reports, updates, and perhaps trying to troubleshoot it a bit).
`----

This article covers all sorts of other situations, centering around the
unkillable process. Some of the info is pretty good, actually.

Google should be able to tell you more, if you need it.

- Mike

--
Registered Linux User #417338, machine #325045.

....and that is how we know the Earth to be banana-shaped.
.

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