Read the followup by pagexec

Read the followup by pagexec

I'll note that bug fixers tend to only look back a short while when considering -stable fixes (if you look at the number of changesets in the various long-term and -stable supported kernels, you will see that they tend to get a lot of fixes initially, but that the rate of fixes tapers off fairly rapidly)

Well, that's an expected curve: current empirical studies show that the distribution / time evolution of software defects goes along a Simon-Yule distribution - which goes down sharper than a bell curve as time goes on.

It's also roughly what you get if you use a simple bug fixing model: take the set of bugs still unfixed, and let bug fixers (developers) random walk the code, then there's a fixed probability to find a bug, with every man-hour spent on looking at the code.

As time goes on, the probability increases that a bug will be found, with a 1-1/t probability, where 't' is the time spent on the code. It will be like a bell-curve for a given difficulty of bug. The 'difficulty' of bugs is a constant parameter, so the combined bug metric would show the integral of 1-d/t ('d': difficulty, 't': time), integrated over 'd' and 't', which would still roughly be a bell curve in practice.

Thus older kernels seeing fewer fixes is natural and expected and is not in itself a sign of less attention.

There's also another aspect: the Cc: stable tag does not typically limit how far a fix is getting ported back - that is decided by the -stable maintainers. They will generally port is back as far as it will still cherry-pick cleanly - and they'll notify the patch submitter if there's a conflict with older stable kernels.

But yes, the older a stable kernel is, the higher the chance that a bug is missed and is not backported - this is a classic trade-off.