There is no reliable way to predict the stress pattern of a polysyllabic word ending in a single vowel letter (i.e. not a vowel digraph) followed by a single L. Some such words have final stress (e.g. lapel, canal, cabal) while others have earlier stress (e.g. label, camel, vial, metal, channel).
There also isn’t any simple link between pronunciation and etymology for words with this spelling pattern. As Janus Bahs Jacquet mentions in a comment, older loans from French are less likely to have final stress than more recent loans.
I think non-final stress is generally more regular for words with this spelling pattern, except for prefixed verbs such as impel, propel, extol, annul, compel.
Even though patrol isn't prefixed, I think the fact that it is commonly used as a verb might have contributed somewhat to its having final stress—both as a verb and as a noun. Even though there are some English noun-verb pairs that are distinguished by stress, such as record (v.) vs. record (n.), it's actually also common for nouns to have the same stress as identically-spelled verbs, as with report, surprise and account.