[tvOS] System.Linq.tests failing with "crashing signal 4"

[vitek-karas]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1068368

Build error leg or test failing: System.Linq.Tests

Affected CI jobs: tvos_arm64_release_allsubsets_mono

Commit range: 3cabc21...b146d75

Extracted Error Log

[18:17:45] dbug: [18:17:36.2657850] 2025-06-14 15:17:36.254 System.Linq.Tests[96970:66913048] 	[PASS] System.Linq.Tests.OrderTests.SortsRandomizedEnumerableCorrectly
[18:17:45] dbug: [18:17:36.2702150] 2025-06-14 15:17:36.257 System.Linq.Tests[96970:66913048] 	[PASS] System.Linq.Tests.OrderTests.SortsRandomizedEnumerableCorrectly
[18:17:45] dbug: [18:17:36.2702570] 2025-06-14 15:17:36.258 System.Linq.Tests[96970:66913048] 	[PASS] System.Linq.Tests.OrderTests.SortsRandomizedEnumerableCorrectly
[18:17:45] dbug: [18:17:36.2826000] 2025-06-14 15:17:36.271 System.Linq.Tests[96970:66913048] 	[PASS] System.Linq.Tests.OrderTests.SortsRandomizedEnumerableCorrectly
[18:17:45] dbug: [18:17:36.3342220] 2025-06-14 15:17:36.322 System.Linq.Tests[96970:66913048] 	[PASS] System.Linq.Tests.OrderTests.SortsRandomizedEnumerableCorrectly
[18:17:45] dbug: [18:17:36.4003420] Xamarin.Hosting: Process '96970' exited with exit code  or crashing signal 4.
[18:17:45] dbug: [18:17:36.4010310] Application 'net.dot.System.Linq.Tests' terminated (with exit code '' and/or crashing signal 4).
[18:17:45] dbug: ==================== End of ApplicationLog ====================
[18:17:45] dbug: 
[18:17:45] dbug: ==================== SystemLog ====================

Error Message

{
  "ErrorMessage": "exited with exit code  or crashing signal 4.",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Description

System.Linq.Tests is experiencing a Signal 4 (SIGILL - Illegal Instruction) crash on tvOS ARM64 release builds with Mono runtime. The test passes individual test cases successfully but crashes with Signal 4 during execution, causing the entire test run to fail with XHarness exit code 92. This appears to be a persistent failure affecting the tvos_arm64_release_allsubsets_mono CI job.

[dotnet-policy-service]

Tagging subscribers to 'os-tvos': @vitek-karas, @kotlarmilos, @ivanpovazan, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-linq
See info in area-owners.md if you want to be subscribed.

[mdh1418]

It seems to affect some iOS lanes as well, e.g. https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-115265-merge-30d30b8f6f7f48a685/System.Runtime.Tests.Attempt.3/1/console.6e3b0fce.log?helixlogtype=result
Ditto with the tvOS lane https://helix.dot.net/api/2019-06-17/jobs/e08b9666-39b4-48d4-948a-6c0fe5eb5833/workitems/System.Runtime.Tests/console
Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1071511&view=logs&j=ffd568e6-d16f-5e80-695c-a9ffc2e0cf22&t=f23ccbcc-ea54-512d-a0e9-93e71c711852

Seems like the pattern matching isn't hitting, maybe cause the console log wasn't uploaded to the artifacts tab of the test view? https://dev.azure.com/dnceng-public/public/_build/results?buildId=1071511&view=ms.vss-test-web.build-test-results-tab&runId=29028722&resultId=100007&paneView=dotnet-dnceng.dnceng-build-release-tasks.helix-test-information-tab
Had to manually navigate through the build/kusto