An experimental integration of LSan with Hotspot has caught at least 3 bugs. One of which has existed since JDK 11 and some of which have been introduced during JDK 20 development. These bugs have been caught by doing one off runs of the tier1 test suite with an LSan-enabled build. The intention is to upstream some variation of https://github.com/jcking/jdk/tree/lsan initially, allowing contributors to make use of it as needed. After that tests that are incompatible with LSan will be skipped when Hotspot is built with LSan. At that point tests can be run with LSan enabled either during GHA, nightly, or during release qualification to more easily catch bugs going forward.

See https://mail.openjdk.org/pipermail/hotspot-runtime-dev/2022-December/058870.html for more reading.