"rmmod -a" doesn't work

[colin]

Hi all,
I tried to use "rmmod -a" to remove all unused modules and found that it
doesn't work.
After tracing the flow, I found that BB passes NULL module name to notify
kernel to do this.
But neither kernel 2.6.12 nor 2.4.28 would consider NULL module name a legal
parameter.
Is "rmmod -a" really workable?

Regards,
Colin