[jdk21u-dev] RFR: 8341862: PPC64: C1 unwind_handler fails to unlock synchronized methods with LM_MONITOR

[Richard Reingruber]

Hi all,

This pull request contains a backport of commit https://github.com/openjdk/jdk/commit/ed6809666b12b0de66f68d5e7e389dde1708aaf3 from the openjdk/jdk repository.

The commit being backported was authored by Richard Reingruber on 16 Oct 2024 and was reviewed by Martin Doerr and Matthias Baesken.

The risk of the backport is low. It's small and therefore obvious that only `LM_MONITOR` is handled differently which is experimental anyway. 

The fix passed our CI testing: JTReg tests: tier1-4 of hotspot and jdk. All of Langtools and jaxp. JCK, SPECjvm2008, SPECjbb2015, Renaissance Suite, and SAP specific tests.
Testing was done with fastdebug builds on the main platforms and also on Linux/PPC64le and AIX.

Thanks, Richard.

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Commit messages:
 - Backport ed6809666b12b0de66f68d5e7e389dde1708aaf3

Changes: https://git.openjdk.org/jdk21u-dev/pull/1186/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1186&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8341862
  Stats: 9 lines in 2 files changed: 8 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1186.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1186/head:pull/1186

PR: https://git.openjdk.org/jdk21u-dev/pull/1186