Re: Kernel version numbers after 4.9.255 and 4.4.255

From: Jiri Slaby
Date: Thu Feb 04 2021 - 06:01:36 EST


On 04. 02. 21, 9:51, Greg Kroah-Hartman wrote:
It might work somewhere, but there are a lot of (X * 65536 + Y * 256 + Z)
assumptions all around the world. So this doesn't look like a good idea.

Ok, so what happens if we "wrap"? What will break with that? At first
glance, I can't see anything as we keep the padding the same, and our
build scripts seem to pick the number up from the Makefile and treat it
like a string.

It's only the crazy out-of-tree kernel stuff that wants to do minor
version checks that might go boom. And frankly, I'm not all that
concerned if they have problems :)

Agreed. But currently, sublevel won't "wrap", it will "overflow" to patchlevel. And that might be a problem. So we might need to update the header generation using e.g. "sublevel & 0xff" (wrap around) or "sublevel > 255 : 255 : sublevel" (be monotonic and get stuck at 255).

In both LINUX_VERSION_CODE generation and KERNEL_VERSION proper.

thanks,
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js