initrd insmod: error inserting '/lib/foo.ko' : -1 operation not permitted

[leo liang]

Hi,

I am trying to add one driver to my kernel.

I have the kernel source and use make all build all the modules and bzImage.

I already have initrd.img in my machine. I extract it to a tmp folder.
Then I copy the driver module into the lib folder. I edited the init
file to insert the module when machine boot. After that, I recreated
the initrd.img by cpio and gzip.

When machine boot,  I got "insmod: error inserting '/lib/foo.ko' : -1
operation not permitted" error.

Did I missed any step? What caused the error?

Thanks.