[noselasd]

I for one am very grateful Red Hat does not do that. We have a kernel driver for custom hardware, there's around 80 of these devices in the world, split roughly 50/50 between Windows and Red Hat users. While these devices are not cheap, we could not recoup the cost of maintaining it if we had to track the upstream kernel all the time - we tried, and could not justify the cost.

The number of times the APIs changes from under your feet is astounding - even with just keeping up with Red Hat, we spend around 4-6 times the engineering time on the driver compared to what we do with the Windows version of the driver, tracking upstream gave us almost an order of magnitude more work (And keep in mind that /only/ supporting the most recent upstream kernel is rarely an option - several versions need to be supported concurrently)

[bonzini]

Red Hat provides a stable ABI for a pretty large set of symbols. Unless you are doing strange things in the driver, a module built for RHEL 7.0 should be fine until 8 comes out.

[noselasd]

That is exactly what I am saying - which is in stark contrast to what would happen if Red Hat did not provide that stable ABI, but instead "Ship exactly what upstream provides" as the original comment suggest they should do.