Currently the guard does not account correctly for ongoing operation if semaphore acquisition fails. It may signal a semaphore when it is not held.
Should be backported to all supported versions.
Closesscylladb/scylladb#19699
* github.com:scylladb/scylladb:
test: add test to check that coordinator lwt semaphore continues functioning after locking failures
paxos: do not signal semaphore if it was not acquired