RFR: 8329757: Crash with fatal error: DEBUG MESSAGE: Fast Unlock lock on stack [v2]
Axel Boldt-Christmas
aboldtch at openjdk.org
Thu Apr 11 05:37:05 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 1-5 done, Tier 6-7 running.
Axel Boldt-Christmas has updated the pull request incrementally with three additional commits since the last revision:
- Drop includes
- Strengthen waiting_monitor assert
- Add explicit break
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/18715/files
- new: https://git.openjdk.org/jdk/pull/18715/files/e11d9b04..d2e8216d
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=18715&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=18715&range=00-01
Stats: 4 lines in 2 files changed: 1 ins; 2 del; 1 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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