If I understand the bug report correctly, the problem seen is at the NFS server side, but the fix goes to the client RPC code. Could you please elaborate what is the scenario we are facing here? Thanks.
8955 bound+reserved ports can be leaked (when NFS client reboots too quickly)
Review Request #810 — Created Jan. 9, 2018 and updated
If an NFS client comes and goes too quickly, the result is "zombie" cm_entries because, without the DEAD flag, such entries won't be cleaned up.
We've been using this change in production for at least 2 years. Originally, we had identified how these cm_entries were leaked (thus bound+reserved ports), and verified this change allowed these cm_entries to be cleaned up (releasing these bound+reserved ports).