On 2023-06-05 22:26, Sam James wrote:
It's just that linux-headers is a special case
Indeed it is. And apparently glibc avoids the copy_file_range bugs by never, ever using copy_file_range internally - which explains why glibc hasn't run into this backward compatibility issue. Presumably once glibc starts assuming kernel 5.3 or later, it can start using copy_file_range internally.
Anyway, thanks for explaining. I installed the patch I mentioned into Gnulib and have updated coreutils accordingly on Savannah master. Please give it a try.