After an upgrade using rpi-update the kernel could be upgraded. The script download the kernel from an other gihub repository rpi-firmware.
Till now, in order to get the kernel source, I download the last kernel source from git://github.com/raspberrypi/linux.git as it is explained in http://elinux.org/RPi_Kernel_Compilation. But the kernel source could be more recent than the one provided by rpi-update.
How to get the kernel source corresponding to the one installed by rpi-update ?