insmod error in kernel module programming

I am just starting with modular programming.

Above are my two files:

hello.c

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

static int hello_init(void)
{
    printk(KERN_ALERT "TEST: Hello world\n");
    return 0;
}

static void hello_exit(void)
{
    printk(KERN_ALERT "TEST: Good Bye");
}

module_init(hello_init);
module_exit(hello_exit);

Makefile

obj-m += hello.o

KDIR = /usr/src/linux-headers-3.13.0-46-generic

all:
    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules

clean:
    rm -rf *.o *.ko *.mod.* *.symvers *.order

And here's my terminal output showing error in insmod command, kindly help.

anubhav@anubhav-Inspiron-3421:~/Desktop/os$ make
make -C /usr/src/linux-headers-3.13.0-46-generic  SUBDIRS=/home/anubhav/Desktop/os modules
make[1]: Entering directory `/usr/src/linux-headers-3.13.0-46-generic'
Building modules, stage 2.
MODPOST 1 modules
make[1]: Leaving directory `/usr/src/linux-headers-3.13.0-46-generic'
anubhav@anubhav-Inspiron-3421:~/Desktop/os$ insmod hello.ko
insmod: ERROR: could not insert module hello.ko: Operation not permitted