[ci-scan] Test failure: GC/API/GC/Collect_Aggressive_LargePages segfaults with SIGSEGV

## Build Information
Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1487780
Build error leg or test failing: coreclr Pri1 Runtime Tests Run GCStandAlone linux x64 checked - GC/API/GC/Collect_Aggressive_LargePages

Pipeline: `runtime-coreclr gc-standalone` (definition 146), branch `main`. The failure reproduces across the GCStandAlone linux legs and persists into follow-up build [1491722](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1491722).

## Error Details

The `GC/API/GC/Collect_Aggressive_LargePages` test crashes with a native segmentation fault (signal 11). The test harness records exit code 139 (128 + SIGSEGV) against an expected 100:

```
Running test: GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd
.../API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.sh: line 248: Segmentation fault (core dumped) $LAUNCHER $ExePath "${CLRTestExecutionArguments[@]}"
Expected: 100
Actual: 139
Failed test: GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd
```

## Error Message

```json
{
"ErrorMessage": [
"Collect_Aggressive_LargePages.sh: line 248:",
"Failed test: GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd"
],
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
```

## First build it occurred
Earliest occurrence in the scanned window is build [1470804](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1470804) (2026-06-18); the segfault then recurs continuously through source build 1487780 and follow-up build 1491722. Persistent across the entire scanned window; true origin may predate 2026-06-18.

## Duplicate search
Searched open and closed `Known Build Error` issues for `Collect_Aggressive_LargePages` and the segfault signature: no existing KBE. Related: previously tracked as dotnet/runtime#127668 (closed 2026-06-17 as completed, but this segfault has continued to recur since that close).

---
_{Filed by the CI outer-loop failure scanner (detection only). Mitigation — a fix PR or owner hand-off — is handled by the companion `ci-failure-fix` workflow, which walks open `[ci-scan]` KBEs.}

> [!NOTE]
> This issue was generated with the assistance of GitHub Copilot (AI). Signatures and build references were verified against public AzDO / Helix logs.

> [!NOTE]
>
> 🔒 Integrity filter blocked 5 items
>
> The following items were blocked because they don't meet the GitHub integrity level.
>
> - [#114222](https://github.com/dotnet/runtime/issues/114222) `search_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
> - [#127541](https://github.com/dotnet/runtime/issues/127541) `search_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
> - [#117370](https://github.com/dotnet/runtime/issues/117370) `search_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
> - [#50848](https://github.com/dotnet/runtime/issues/50848) `search_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
> - [#19341](https://github.com/dotnet/runtime/issues/19341) `search_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
>
> To allow these resources, lower `min-integrity` in your GitHub frontmatter:
>
> ```yaml
> tools:
> github:
> min-integrity: approved # merged | approved | unapproved | none
> ```
>
>

> Generated by [CI Outer-Loop Failure Scanner](https://github.com/dotnet/runtime/actions/runs/28725306699/agentic_workflow) · ● 12.9M · [◷](https://github.com/search?q=repo%3Adotnet%2Fruntime+is%3Aissue+%22gh-aw-workflow-call-id%3A+dotnet%2Fruntime%2Fci-failure-scan%22&type=issues)

### Report

|Build|Repository|Test|Pull Request|
|---|---|---|---|
|[1594615](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594615)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594615&view=ms.vss-test-web.build-test-results-tab&runId=44020578&resultId=103822)||
|[1590860](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1590860)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1590860&view=ms.vss-test-web.build-test-results-tab&runId=43915752&resultId=104196)||
|[1587258](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1587258)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1587258&view=ms.vss-test-web.build-test-results-tab&runId=43805432&resultId=103797)||
|[1584864](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1584864)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1584864&view=ms.vss-test-web.build-test-results-tab&runId=43730478&resultId=103721)||
|[1580816](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1580816)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1580816&view=ms.vss-test-web.build-test-results-tab&runId=43610600&resultId=104171)||
|[1574173](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574173)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574173&view=ms.vss-test-web.build-test-results-tab&runId=43378906&resultId=103725)||
|[1570365](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1570365)|dotnet/runtime|[GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1570365&view=ms.vss-test-web.build-test-results-tab&runId=43243326&resultId=104207)||
#### Summary
|24-Hour Hit Count|7-Day Hit Count|1-Month Count|
|---|---|---|
|0|3|7|

Start with the GC/API/GC/Collect_Aggressive_LargePages/Collect_Aggressive_LargePages.cmd test and its Linux shell output in the linked Azure DevOps builds. Compare the recurring SIGSEGV with the history of dotnet/runtime#127668 and inspect the test results and crash details. Done means the test completes without exit code 139 across the affected GCStandAlone Linux legs.

Written by the indexing model from the issue text.