This series backports the patchset
"exit: Put an upper limit on how often we can oops"
(https://lore.kernel.org/linux-mm/20221117233838.give.484-kees@xxxxxxxxxx/T/#u)
to 5.15, as recommended at
https://googleprojectzero.blogspot.com/2023/01/exploiting-null-dereferences-in-linux.html