Suppose I have a particular release of Ubuntu (say Ubuntu 12.04.5 LTS - Precise Pangolin). The kernel it uses is 3.13.0-32-generic x86_64. Where exactly does this version number come from? It is clearly not mainline kernel version 3.13. By looking at
/usr/include/linux/version.h in 12.04.5 I found
LINUX_VERSION_CODE 197199 that translates to 3.2.79, which looks more plausible, but there is also mainline v3.2.79-precise which seems to correspond to v3.2.79. Is this equivalent to 12.04.5s 3.13.0-32 kernel?
How can I find out the exact mainline kernel, a particular version of Ubuntu is based on? I'm interested in finding out how to get to this 3.13.0-32 using the exact mainline kernel commit it uses.