I can get “df” to become reply blocked forever. My “off the cuff” diagnosis
is that devb-fdc missed the unblock pulse and is hosed.
I was doing some heavy disk I/O on an SMP box. Specifically, I was "mv"ing
files from one directory to another (i.e., mv /xdata /data, where the /xdata
directory has a lot of stuff).
Then, on a different console, I ran “df -kP”. This always hangs for a while
as it goes and diddles the floppy. It sat there for a bit, so I decided to
abort it with ^C. No luck.
At this point, devb-fdc is in the “odd state”. That “df” turned out to be
unkillable. It still sits on my system as REPLY blocked on devb-fdc.
Any attempts to kill “df” fail – kill -9, slay, etc, appear to do their thing
but the “df” still sits there.
The only way to fix it is to kill -9 devb-fdc.
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Consulting and Training at www.parse.com
Email my initials at parse dot com.