Linux Kernel Programming - Module 2 unable to get symbols exported by Module 1

Question

I have a Linux kernel module M1 which exports a symbol S1. When I insmod M1.ko, I can see S1 in /proc/kallsyms. I use S1 in another kernel module M2. When I compile and insert module M2, I get message in dmesg saying "Unknown symbol in module S1".

I am stumped. Can someone please tell me what is going wrong? I am using Ubuntu 9.10.

Answer 1

Is the symbol really exported? If you ask for a modinfo dump of the symbols from M1, is it there?