RFR: 8329757: Crash with fatal error: DEBUG MESSAGE: Fast Unlock lock on stack [v4]

Axel Boldt-Christmas aboldtch at openjdk.org
Thu Apr 11 18:22:08 UTC 2024


> `Deoptimization::relock_objects` may reorder locks within in the `LockStack` which are added inside the same vframe. This can be handled by the interpreter but if OSR has occurred C2 may observe this invalid order in the `LockStack`, which breaks its assumption leading to incorrect behaviour.
> 
> This patch functionally makes sure that the LockStack is always consistent by always inflating eliminated locks when `Deoptimization::relock_objects`  is called.
> 
> It also adds verification code which checks that the LockStack is consistent with the lock order observed inside the deoptimized vframes. 
> 
> Note: for leaf deoptimizations we have enough information to recreate a correct top of the LockStack with minimal inflations, however that should be a separate RFE. This only inflates eliminated locks so the worth of solving that may be minimal or even detrimental. 
> 
> Tests still running. Tier 1-7 done.

Axel Boldt-Christmas has updated the pull request incrementally with one additional commit since the last revision:

  Change to ASSERT

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18715/files
  - new: https://git.openjdk.org/jdk/pull/18715/files/12d112bc..077b62af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18715&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18715&range=02-03

  Stats: 10 lines in 3 files changed: 5 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/18715.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18715/head:pull/18715

PR: https://git.openjdk.org/jdk/pull/18715


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