[jdk17u-dev] Integrated: 8328085: C2: Use after free in PhaseChaitin::Register_Allocate()

[Richard Reingruber]

On Thu, 9 Jan 2025 14:37:36 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> Hi all,
> 
> This pull request contains a backport of commit [a21862ab](https://github.com/openjdk/jdk21u-dev/commit/a21862ab00317842da006eae453865badd4dc30f) from the [openjdk/jdk21u-dev](https://git.openjdk.org/jdk21u-dev) repository.
> 
> The commit being backported was authored by Richard Reingruber on 17 Dec 2024 and had no reviewers.
> 
> I'd consider the risk medium. There could be scenarios with higher memory usage in c2 register allocation.
> I've done some testing with which did not reveal higher higher memory usage.
> (the measuring code was part of the [original pull request](https://github.com/openjdk/jdk/pull/22200/commits))
> 
> 
> Max. ResourceArea size in KB after C2 PhaseChaitin::merge_multidefs
> 
> DaCapo Benchmark        Basline        Pull Request
> 
> avrora                  2273           2259
> batik                   3456           3179
> biojava                 3372           3541
> cassandra               563            595
> eclipse                 4044           4090
> fop                     3986           3986
> graphchi                3024           3024
> h2                      3826           3712
> h2o                     5750           5962
> jme                     2209           2147
> jython                  9734           9774
> kafka                   3115           3493
> luindex                 3380           3447
> lusearch                3866           3381
> pmd                     6497           5779
> spring                  4771           4944
> sunflow                 3088           3088
> tomcat                  3375           3467
> tradebeans              3348           3672
> tradesoap               3480           3353
> xalan                   3476           3106
> zxing                   3741           4766
> 
> 
> `zxing` results are volatile. I've made 3 additional runs:
> 
> Max. ResourceArea size in KB after C2 PhaseChaitin::merge_multidefs running DaCapo::zxing
> 
> Baseline:     3844 6146 5448
> Pull Request: 6013 3615 4472
> 
> 
> 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.

This pull request has now been integrated.

Changeset: 54914367
Author:    Richard Reingruber <rrich at openjdk.org>
URL:       https://git.openjdk.org/jdk17u-dev/commit/54914367b854afe577f7002e8a5505ff5aabb528
Stats:     1 line in 1 file changed: 0 ins; 1 del; 0 mod

8328085: C2: Use after free in PhaseChaitin::Register_Allocate()

Backport-of: a21862ab00317842da006eae453865badd4dc30f

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

PR: https://git.openjdk.org/jdk17u-dev/pull/3197