How ubuntu update its stable kernel?

[kalpana]

I found there's difference between ubuntu latest kernel version and upstream kernel version(from kernel.org stable version), I know ubuntu would apply security update soon after CVE be public, but there are lots of stable commit which is relevant to small bug fix not security issue and do not have CVE number.

I wonder know what strategy ubuntu has to apply those non-CVE stable kernel commit to ubuntu kernel? Does any official docs talking about it?