From: Rusty Russell <rusty@rustcorp.com.au>

I *do* want to add a check for a truncated module, since that's probably
the most common case (^C on "make modules_install").  But I don't want to
double the size of module.c with every check I can think of.

tested with:
# bs=0; while [ $bs -lt 3764 ]; do
   dd if=dummy.ko bs=$bs count=1 2>/dev/null | insmod -;
   bs=`expr $bs + 1`;
  done