Android : how to expose API in kernel .... getting linker error

How to expose an API in kernel (I am working on Android)? Somehow the following does not work....

1. I did EXPORT_SYMBOL(module1_func) in module1.c


2. did "extern module1_func();" in header file - module1.h (placed the header file in ''kernel/include/linux')


3. In module2.c, I did "#include " & called the function "module1_func()"

FYI: module1.c is in 'kernel/security/' AND module2.c is in 'kernel/mm'

After compilation I am getting the following error. BTW I did clean build, still the same.. Please suggest!!

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kernel/mm/built-in.o: In function get_param': :(.text+0x75c0): undefined reference tomodule1_func' make: * [.tmp_vmlinux1] Error 1