+% TODO: con il kernel 5.14 è stata introdotta la syscall memfd_secret, vedi
+% https://lwn.net/Articles/835342/ https://lwn.net/Articles/812325/
+% https://lwn.net/Articles/865256/
+% https://lwn.net/ml/linux-mm/20210729082900.1581359-1-rppt@kernel.org/ e
+% https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1507f51255c9
+