LINUX: order of statically linked module loading

Question

If I have two modules which are being statically linked in. One modules' module_init function depends on another module's module_init function having already run. Is there a way to force one module to load before the other?

Also, is the first module's init function guaranteed to finish before the second one is invoked?

Lastly, if the answer to the above is NO, what is the recommended way of synchronizing the two module init calls to make sure I don't run into issues?

Answer 1

Is there a way to force one module to load before the other?

Answer is surprisingly simple, make sure first module is first in Makefile:

obj-y += mod1.o
obj-y += mod2.o

is the first module's init function guaranteed to finish before the second one is invoked?

Yes, initcalls (module_init hook) in your case are called one-by-one. See init/main.c, do_one_initcall() callers.

Answer 2

I'm assuming you want to fix the static initialization fiasco

Have a look at

• http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Attributes.html (init_priority)
• How exactly does __attribute__((constructor)) work?
• the -rdynamic linker flag for gcc/ld (this gives you some latitude to do compile time linking, and still use the runtime loader (dload))

Static Initialization Order Fiasco