Sorry, aimed for a technically precise title and didn't want to bait clicks.

Yes, this does not affect people on stock configurations for the plain reason that they wouldn't expect the volume key to be safe during suspend anyway.

Debian's solution was ported to several (most?) other distributions and I guess quite a few people maintained private ports.

The thread-keyring(7) manpage promises: "A thread keyring is destroyed when the thread that refers to it terminates." For their key upload (from userspace to kernelspace) mechanism, the cryptsetup project relied on this property; but kernel 6.9 introduced a regression invalidating this property.