[ci-scan] Test failure: GC/Regressions/Github/Runtime_129681 Crossgen2 exit 255 on osx x64 R2R

[github-actions]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1545184
Build error leg or test failing: coreclr Pri1 Runtime Tests Run R2R_CG2 osx x64 checked — GC/Regressions/Github/Runtime_129681/Runtime_129681

Pipeline: runtime-coreclr outerloop (definition 108), branch main. The failure reproduces on the R2R_CG2 osx x64 checked leg and persists into follow-up build 1545348.

Error Details

The GC/Regressions/Github/Runtime_129681 test compiles its assembly with Crossgen2 (R2R composite, --method-layout:random, --verify-type-and-field-layout) before running. On the osx x64 leg targeting osx/x64, Crossgen2 aborts with exit code 255, so the test harness records a non-zero exit and the test fails.

Running test: GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd
Running CrossGen2:  crossgen2 @...Runtime_129681.dll.rsp
Crossgen2 failed with exitcode: 255
Test Harness Exitcode is : 1
END EXECUTION - FAILED

Error Message

{
  "ErrorMessage": [
    "Running test: GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd",
    "Crossgen2 failed with exitcode: 255"
  ],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

First build it occurred

The signature is present in source build 1545184 (2026-08-08), the prior build 1544819 (2026-08-07), and follow-up build 1545348 (2026-08-08) — at least three consecutive occurrences.

Duplicate search

Searched open and closed issues/KBEs for Runtime_129681 and Crossgen2 failed with exitcode: 255 on the osx x64 R2R leg: no existing KBE matches. Merged PR #131947 ("Fix AV in gc_heap::init_heap_segment", merged 2026-08-07) is unrelated to this Crossgen2 codegen failure and merged before the follow-up build that still reproduces the signature.

---

Filed by ci-failure-scan (detection only). ci-failure-fix walks open [ci-scan] KBEs and either opens a small fix PR or comments here to loop in owners — it never disables the test.

Note

This issue was generated by the ci-failure-scan Copilot (AI) automation workflow. Signatures and build references were verified against public AzDO / Helix logs.

Warning

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Generated by CI Outer-Loop Failure Scanner · 489 AIC · ⌖ 16.4 AIC · ⊞ 18.3K · ◷

Report

Build	Repository	Test	Pull Request
1545742	dotnet/runtime	GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd
1545710	dotnet/runtime	GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd
1545681	dotnet/runtime	GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd
1545624	dotnet/runtime	GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd
1545609	dotnet/runtime	GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd
1545482	dotnet/runtime	GC/Regressions/Github/Runtime_129681/Runtime_129681/Runtime_129681.cmd

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
6	6	6

[dotnet-policy-service]

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

[jkotas]

New test introduced by #131947

[github-actions]

Workflow artifact: ci-fix
Artifact kind: handoff
Linked KBE: #132037

Note

AI/Copilot-generated triage note.

This Known Build Error has no producible automated code change (reason: Crossgen2 R2R codegen failure — must not be auto-fixed), so I could not open even a best-effort PR. Looping in owners so it can be fixed forward rather than muted.

Root cause (best analysis)

On the R2R_CG2 osx x64 checked leg (pipeline runtime-coreclr outerloop, definition 108), the GC/Regressions/Github/Runtime_129681 test pre-compiles its assembly with Crossgen2 as an R2R composite image (--method-layout:random --verify-type-and-field-layout) before executing. Crossgen2 aborts with exit code 255:

Running CrossGen2:  crossgen2 @...Runtime_129681.dll.rsp
Crossgen2 failed with exitcode: 255
Test Harness Exitcode is : 1

Because Crossgen2 fails during ahead-of-time compilation, the test never runs and the harness records a non-zero exit. Exit code 255 from Crossgen2 on the osx/x64 target with --verify-type-and-field-layout points at a compiler-side abort (assert / unhandled exception in the R2R compilation path), not at the test's own logic. Diagnosing it requires the Crossgen2 stderr/assert output, which is a JIT/R2R-codegen investigation outside the safe automated-fix bounds. Disabling the test is explicitly not an option for this workflow.

Evidence

• Failing build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1545184
• First build it occurred: build 1544819 (2026-08-07); reproduces in 1545184 and follow-up 1545348 (2026-08-08) — at least three consecutive builds (computed within the scanned window; may not be the true origin)
• Possible related PR: none identified with sufficient confidence

Suggested reviewers / area contacts

• Likely author: none identified with sufficient confidence
• Area owners (area-GC-coreclr): @anicka-net, @dotnet/gc
• The Crossgen2/R2R abort likely also needs CodeGen eyes (area-CodeGen-coreclr): @JulieLeeMSFT, @dotnet/jit-contrib

A fix would likely involve capturing the Crossgen2 stderr/assert from the failing osx-x64 R2R composite compilation of Runtime_129681.dll and addressing the compiler abort surfaced by --verify-type-and-field-layout.

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• awmgmcpg

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "awmgmcpg"

See Network Configuration for more information.

Generated by CI Outer-Loop Failure Fixer · 206.5 AIC · ⌖ 15.4 AIC · ⊞ 17.1K · ◷