In the Linux kernel, the following vulnerability has been resolved:
s390/bpf: Fix bpfarchtextpoke() with newaddr == NULL again
Commit 7ded842b356d ("s390/bpf: Fix bpfplt pointer arithmetic") has accidentally removed the critical piece of commit c730fce7c70c ("s390/bpf: Fix bpfarchtextpoke() with newaddr == NULL"), causing intermittent kernel panics in e.g. perf's onswitch() prog to reappear.
Restore the fix and add a comment.