rand: note that locking needs to be explicitly enabled.
Fixes
@@ -311,6 +311,12 @@ or the properties in the case of B<OSSL_RAND_PARAM_PROPERTIES>.
=back
+=head1 NOTES
+
+An B<EVP_RAND_CTX> needs to have locking enabled if it acts as the parent of
+more than one child and the children can be accessed concurrently. This must
+be done by explicitly calling EVP_RAND_enable_locking().
+
=head1 RETURN VALUES
EVP_RAND_fetch() returns a pointer to a newly fetched B<EVP_RAND>, or
