Hello, I'm getting hit by a problem that was discussed here last january (thread starts at http://mail.nl.linux.org/kernelnewbies/2006-01/msg00460.html). Basically, I'm working with multiple out-of tree kernel modules which export symbols used by one another. At compile time, modpost warns about undefined symbols, which are defined in one of those modules and used in another one. Note however that modules work fine. Question is: when multiple out-of tree modules depend on one another, how is it possible to tell modpost to look for symbols in directories other than where it looks by default. The full test source follows, the warning I'm trying to get rid of is the following line: *** Warning: "sharedFunction" [/root/k/b/b.ko] undefined! Thanks, Jean-Marc Ranger ---------- debian:~# debian:~# dmesg -c > /dev/null debian:~# uname -a Linux debian 2.6.8-3-686 #1 Thu May 25 02:27:57 UTC 2006 i686 GNU/Linux debian:~# gcc --version gcc (GCC) 3.3.5 (Debian 1:3.3.5-13) Copyright (C) 2003 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. debian:~# cd k debian:~/k# find . . ./a ./a/Makefile ./a/a.c ./b ./b/b.c ./b/Makefile debian:~/k# cat a/Makefile ifeq ($(KERNELRELEASE),) KERNEL_DIR ?= /lib/modules/$(shell uname -r)/build PWD := $(shell pwd) modules: $(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules modules_install: $(MAKE) -C $(KERNEL_DIR) M=$(PWD) INSTALL_MOD_PATH=$(MODULES_DIR) modules_install clean: rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions .PHONY: modules modules_install clean else obj-m := a.o endif debian:~/k# cat a/a.c #include <linux/config.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> MODULE_LICENSE ("GPL"); void sharedFunction(const char* string) { printk(KERN_WARNING "sharedFunction reports: %s\n", string); } int __init A_init(void) { sharedFunction("DriverA"); return 0; } void __exit A_exit(void) { } module_init(A_init); module_exit(A_exit); EXPORT_SYMBOL(sharedFunction); debian:~/k# cat b/Makefile ifeq ($(KERNELRELEASE),) KERNEL_DIR ?= /lib/modules/$(shell uname -r)/build PWD := $(shell pwd) modules: $(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules modules_install: $(MAKE) -C $(KERNEL_DIR) M=$(PWD) INSTALL_MOD_PATH=$(MODULES_DIR) modules_install clean: rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions .PHONY: modules modules_install clean else obj-m := b.o endif debian:~/k# cat b/b.c #include <linux/config.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> MODULE_LICENSE ("GPL"); void sharedFunction(const char* string); int __init B_init(void) { sharedFunction("DriverB"); return 0; } void __exit B_exit(void) { } module_init(B_init); module_exit(B_exit); debian:~/k# make -C a make: Entering directory `/root/k/a' make -C /lib/modules/2.6.8-3-686/build M=/root/k/a modules make[1]: Entering directory `/usr/src/kernel-headers-2.6.8-3-686' CC [M] /root/k/a/a.o Building modules, stage 2. MODPOST CC /root/k/a/a.mod.o LD [M] /root/k/a/a.ko make[1]: Leaving directory `/usr/src/kernel-headers-2.6.8-3-686' make: Leaving directory `/root/k/a' debian:~/k# make -C b make: Entering directory `/root/k/b' make -C /lib/modules/2.6.8-3-686/build M=/root/k/b modules make[1]: Entering directory `/usr/src/kernel-headers-2.6.8-3-686' CC [M] /root/k/b/b.o Building modules, stage 2. MODPOST *** Warning: "sharedFunction" [/root/k/b/b.ko] undefined! CC /root/k/b/b.mod.o LD [M] /root/k/b/b.ko make[1]: Leaving directory `/usr/src/kernel-headers-2.6.8-3-686' make: Leaving directory `/root/k/b' debian:~/k# insmod a/a.ko debian:~/k# insmod b/b.ko debian:~/k# dmesg -c sharedFunction reports: DriverA sharedFunction reports: DriverB debian:~/k# logout -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
