Corpus for keyctl$update:

Coverage	Program
654	perf_event_open-add_key$keyring-add_key$user-keyctl$update
295	add_key$user-keyctl$update
270	keyctl$set_timeout-perf_event_open-request_key-keyctl$search-add_key$fscrypt_v1-keyctl$update-keyctl$get_security-request_key
126	perf_event_open-readv-keyctl$update
25	keyctl$update