Looking at  get_task_comm patch:
http://linus.bkbits.net:8080/linux-2.5/patch@1.1803.144.3

There is one other place where task->comm is accessed outside current.
There are two issues.  The code is trying to copy to temp space without
task_lock.  It is not using temp space for actual user copy.

Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>