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hookenz
Asked: 2014-05-09 20:32:47 +0800 CST

Is it possible to compile a kernel module under chroot?

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Under a chroot environment, is it possible to build a kernel module without having the kernel installed, just the headers?

It sounds like something you wouldn't want to do, but in my case I do. I've got a script that automates creating an environment for netbooting which also includes the initrd.img created by mkinitramfs and copied to the tftp server afterward.

For example, if the target PC also includes a radeon card I want fglrx. If it's nvidia I want the nvidia package. Those who run/customise the build script may not have those cards installed physically into my PC.

kernel

1 Answers

  1. Yes.

    For Ubuntu you really just need the linux-headers-* packaged installed for the desired target. Here is an example Makefile that sets KDIR to a custom header location:

    obj-m := example.o                                                              
KDIR := /usr/src/linux-headers-4.2.0-18-generic                                
PWD := $(shell pwd)                                                             
default:                                                                        
        $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules                               
clean:                                                                          
        $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean

    This should work just the same inside a chroot.

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