[PLUG] killing "D" state processes?

[Shannon C. Dealy]

On 14 May 2002, Russell Senior wrote:

[snip]
> Shannon> What kernel version are you running?
>
> "uname" says 2.4.16.  Oddly, about 5 minutes after I sent the message,
> the process went away and I could at least "mt status" the drive.
> But, when I tried to rewind, it hung again.  I am getting messages in
> the logs that indicate some kind of failure (either communication or
> hardware, not sure yet).  They look like:
>
>    May 14 14:57:41 coulee kernel: scsi : aborting command due to timeout : pid 13945266, scsi0, channel 0, id 5, lun 0 Rezero Unit 00 00 00 00 00
>    May 14 14:57:41 coulee kernel: scsi0: Aborting CCB #7064897 to Target 5
>    May 14 14:57:41 coulee kernel: scsi0: CCB #7064897 to Target 5 Aborted
>    May 14 14:57:41 coulee kernel: st0: Error 26030000 (sugg. bt 0x20, driver bt 0x6, host bt 0x3).
>
> I am thinking a nice gentle reboot at this point might clear it up.

This sounds like a problem with your SCSI bus.  Some controllers and/or
tape drives are very picky about the signal quality, cabling, what else is
on the bus and even what they will talk to.  I have a DDS-3 tape drive
which will not run reliably if any other SCSI device is on the bus with
it, so I finally just bought a separate SCSI controller for it which got
rid of the problems.  My experience with SCSI has been always buy name
brand controllers (preferably adaptec), use high quality cables, and avoid
anything from Seagate or any of the companies they bought out.

If you built your SCSI drivers as modules and you don't have any critical
hard drives connected to the controller, you can simply unload and reload
the SCSI driver to clear up any driver/kernel related issues, though if
you have hardware bus problems this won't really help for the long haul.

Shannon C. Dealy      |               DeaTech Research Inc.
dealy at deatech.com     |          - Custom Software Development -
                      |    Embedded Systems, Real-time, Device Drivers
Phone: (800) 467-5820 | Networking, Scientific & Engineering Applications
   or: (541) 451-5177 |                  www.deatech.com