A small robustness fix in ThreadsSMRSupport::print_info_on() to reduce the likelihood of crashes during error reporting. Uses Threads_lock->try_lock() for safety and restricts some reporting to when the Threads_lock has been acquired (depends on JDK-8256383). Uses a ThreadsListHandle to make the current ThreadsList safe for reporting (depends on JDK-8258284). Also detects when the system ThreadsList (_java_thread_list) has changed and will warn that some of the reported info may now be stale.
Two existing tests have been updated to reflect the use of a ThreadsListHandle in ThreadsSMRSupport::print_info_on(). Mach5 Tier[1-6] testing has no regressions. ------------- Commit messages: - 8231627: runtime/ErrorHandling/ThreadsListHandleInErrorHandlingTest.java fails because error occurred during printing all threads Changes: https://git.openjdk.java.net/jdk/pull/1891/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1891&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8231627 Stats: 68 lines in 3 files changed: 39 ins; 5 del; 24 mod Patch: https://git.openjdk.java.net/jdk/pull/1891.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/1891/head:pull/1891 PR: https://git.openjdk.java.net/jdk/pull/1891
