Question

I’m trying to write a makefile for a kernel module and cannot get it to work. Running the following has this output

$ make
make: Nothing to be done for 'all'.

but running the make command directly on the terminal results in

$ make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
make: Entering directory '/usr/src/linux-headers-3.5.0-17-generic'
   CC [M] <blah>
   Building modules, stage 2
   <blah>
make: Leaving directory...

The contents of my Makefile are (source file is main.c)

obj-m += main.o
all:
    make -C /lib/modules/$(shell uname -r)/build M=$(shell pwd) modules

I do delete *.o and *.ko before trying to use the makefile. Changing all to default does nothing either.

Answer 1

The most likely issue is that you didn’t use a real tab character to begin the line reading make -C ..., but instead used multiple spaces. make requires that commands all begin with a tab character.