Installing a new kernel image is quite simple thanks to the buildroot utility. A number of steps must be followed:

1 - Download latest Buildroot


2 - Generate Buildroot preset config

make qemu_x86_defconfig 	# EXAMPLE ARCH
make menuconfig

* Change the following for Kernel Debugging support:
      * In Build options, toggle build packages with debugging symbols.
      * In Toolchain, change linux version to desired one
      * In Toolchain, change Custom kernel version headers to desired ones
      * In Kernel, change Kernel version to desired one

3 - Download Kernel source and configure it

make linux-menuconfig

* Change the following for Kernel Debugging support:

      *	In Kernel hacking, toggle Kernel Debugging
      * Under Kernel hacking in Compile-time checks and compiler options toggle
		- Compile kernel with debug infopp
		- Provide GDB sripts for kernel debugging`
		- Compile kernel with frame pointers

4 - Build your kernel


5 - Run Kernel

Once you have covered all steps, The following files should have been created:

* Kernel source code at output/build/linux-XXX
* Compressed kernel image at output/images/bzImage
* Root filesystem (rootfs) at output/images/rootfs.ext2
* Raw kernel image at output/build/linux-XXX/vmlinux

Done! all we got left is to execute the kernel image with qemu:

qemu-system-xx  -kernel images/bzImage  	\
		-hda images/rootfs.ext2 	\
		-append "root=/dev/sda rw" 	\
		-s 				\

On another terminal execute gdb under the linux kernel directory:

(gdb) add-auto-load-safe-path output/build/linux-4.9.6/scripts/gdb/
(gdb) file output/build/linux-XXX/vmlinux
(gdb) target remote :1234
(gdb) break init
(gdb) c