On Mon, 21 Sep 2026 07:10:00 GMT, David Carlier <[email protected]> wrote:
>> …ring on its error paths >> >> Found while sweeping the JVMTI error paths. >> `JvmtiEnvBase::set_native_method_prefixes()` >> copies the agent's prefixes one at a time with `os::strdup()`, and when it >> meets a null >> entry, or a copy that fails, it frees what it has already copied before >> returning. Both >> cleanup loops stop at `i - 1` while the array is populated up to `i`, so the >> prefix copied >> last is never freed and every rejected call leaks one string. Only >> `SetNativeMethodPrefixes` >> with more than one prefix can get there, since `SetNativeMethodPrefix` >> always passes a count >> of one. >> >> The fix is to run both loops to `i`, which also keeps the case where nothing >> has been copied >> yet correct. >> >> The test has an agent call `SetNativeMethodPrefixes` with a one megabyte >> prefix followed by a >> null entry, and compares the Internal figure NMT reports before and after. >> An unfixed VM grows >> by the full amount of the rejected copies, a fixed one stays flat. >> >> Additional testing: >> >> - [ ] linux-x86_64 fastdebug, serviceability/jvmti >> - [ ] Regular testing pipelines >> >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > David Carlier has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains two commits: > > - use NMT Serviceability instead > - 8392739: JvmtiEnvBase::set_native_method_prefixes leaks one prefix string > on its error paths Marked as reviewed by dholmes (Reviewer). ------------- PR Review: https://git.openjdk.org/jdk/pull/32969#pullrequestreview-5314524492
