Clash Royale CLAN TAG#URR8PPP

Inserting custom module taints kernel

I just want to insert a module without tainting the kernel.

This is the file test1.c

test1.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>

MODULE_LICENSE("GPL")
MODULE_AUTHOR("AUTHOR")
MODULE_DESCRIPTION("DESCRIPTION")

static int __init module_hello(void)
printk(KERN_ALERT "Hello");
return 0;


static void __exit module_bye(void)
printk(KERN_ALERT "Bye");


module_init(module_hello);
module_exit(module_bye);


and in the same folder, the file Makefile, as decribed in kernel.org section 3

Makefile

ifneq ($(KERNELRELEASE),)

obj-m := test1.o

else

KDIR ?= /lib/modules/`uname -r`/build

default:
$(MAKE) -C $(KDIR) M=$$PWD

endif


Executing make creates the necessary files correctly, but when I insert it I get the message Loading out-of-tree modules taints kernel, and I don't get the output of the module_hello until I remove the module, and after that, if I insert it again I get the message from the module_bye function, but not the hello one.

make

Loading out-of-tree modules taints kernel

module_hello

module_bye

2 Answers
2

The delay in message is because of missing n at the end of each print. a n puts the data from the kernel message buffer to file.

n

n

For the tainted kernel refer to this link

As in kernel.org section 1,

[...] all modules are initially developed and built
out-of-tree.

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