Justin Piszcz wrote:

# ps auxww | grep D
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root       273  0.0  0.0      0     0 ?        D    Oct21  14:40 [pdflush]
root       274  0.0  0.0      0     0 ?        D    Oct21  13:00 [pdflush]

After several days/weeks, this is the second time this has happened,
while doing regular file I/O (decompressing a file), everything on the
device went into D-state.

The next time you come across something like that, do a SysRq-T dump and
post that.  It shows a stack trace of all processes - and in particular,
where exactly each task is stuck.

/mjt