Processes in uninterruptible sleep
I am having a periodic issue with a server program, where it will go into uninterruptible sleep (D state) for no reason that I can discern. I am running the release version of OpenSuse 10.3, with kernel version 126.96.36.199-31-default x86-64. My server does basic file, socket, and mysql I/O and the mysql server does not go to D state when my program does. my program is a typical multi-process unix-type server that forks to handle client connections. the interesting thing is that the server runs on 3 ports to handle connections from various locations with differing network and firewall configurations, and only one port (port 80 but not HTTP) goes into D state. the other two continue to function normally. even stranger yet, the parent and ALL of its children go into D state at the same time. I've been googling for over an hour looking for known bugs in the opensuse 10.3 default kernel, and haven't found anything useful. do any of you know of anything that might cause a parent process and all of its children to go into D state simultaneously on this system? just looking for more things to rule out before I start looking at hardware.
I know it's customary to show source code that exhibits the problem, but since I can't reproduce the problem on command, I don't know if source code would really be useful in this case.