It looks like this change to the Linux kernel caused the break. Not knowing the purpose or scope of COMPAT, it's hard to say what it was meant to improve.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5180e3e24fd3e8e7ea46fbe21e10f5ea3fb1edaa
It looks like this change to the Linux kernel caused the break. Not knowing the purpose or scope of COMPAT, it's hard to say what it was meant to improve.
https:/ /git.kernel. org/pub/ scm/linux/ kernel/ git/torvalds/ linux.git/ commit/ ?id=5180e3e24fd 3e8e7ea46fbe21e 10f5ea3fb1edaa