Build Information
Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1409132
Build error leg or test failing: System.Runtime.Tests.WorkItemExecution
Pull request: #127503
Error Message
DO NOT USE JSON BELOW IF THIS IS A BUILD BREAK otherwise build analysis will allow pull requests to merge that break the build worse. For a build break, do not use this issue form. Make a regular new issue.
Fill the error message using step by step known issues guidance.
{
"ErrorMessage": "The app 'net.dot.System.Runtime.Tests' terminated with signal 9",
"BuildRetry": false,
"ExcludeConsoleLog": false
}System logs for the run contain the following lines:
launchd: [user/501/UIKitApplication:net.dot.System.Runtime.Tests[2d42][rb-legacy] [27597]:] exited with exit reason (namespace: 3 code: 0x2) - OS_REASON_CODESIGNING, ran for 365ms
SpringBoard: (RunningBoardServices) [com.apple.runningboard:process] Firing exit handlers for 27597 with context <RBSProcessExitContext| specific, status:<RBSProcessExitStatus| domain:codesigning(3) code:invalid-page(2)>>
Copilot's analysis of the logs
the cause is a code-signing failure.
Test log evidence
- The app runs only ~365 ms before App terminated due to signal 9 — too fast for a memory/jetsam kill.
Device system log (device-DNCENGOSX118-...log) — the smoking gun The kernel killed the process for a code-signing reason, not OOM:
line 10470: launchd: ... exited with exit reason (namespace: 3 code: 0x2) - OS_REASON_CODESIGNING, ran for 365ms
line 10552: SpringBoard: ... <RBSProcessExitStatus| domain:codesigning(3) code:invalid-page(2)>
line 10555: FrontBoard: ... [app<net.dot.System.Runtime.Tests>:27597] Process exited: ... codesigning(3) code:invalid-page(2)
codesigning / invalid-page means the kernel tried to validate a page of the app's mach-o at runtime and found a hash mismatch against the embedded code signature — the kernel responds with SIGKILL. (Note: jetsam priority was just set to 100 with a 2098 MB soft limit; no jetsam/memorystatus kill events appear for pid 27597.)
Mac host system log (macos.system.log) — the likely upstream cause A few seconds before the launch, the host ran codesign and trust evaluation produced repeated failures:
14:06:57.117–.120 codesign[43362]: CSSM Exception: -2147409622 CSSMERR_TP_NOT_TRUSTED (×8)
14:06:57.121 codesign[43362]: open(/private/var/db/DetachedSignatures) - No such file or directory
CSSMERR_TP_NOT_TRUSTED means the signing identity's trust chain didn't validate during the (re)sign step. Combined with the device-side invalid-page exit, this strongly points to the app being signed with an untrusted/broken signing identity (or the resign step producing a corrupt signature), so the iOS kernel rejected pages of the binary as soon as they were paged in and killed the process.
Bottom line: The test wasn't killed for memory or test-runner reasons. It was killed by the iOS kernel's code-signing enforcement (OS_REASON_CODESIGNING / invalid-page), most likely caused by the failing/untrusted codesign step seen on the Mac host (CSSMERR_TP_NOT_TRUSTED) right before the launch. Fixing the signing identity / provisioning on the Mac should resolve it.
Known issue validation
Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1409132
Error message validated: [The app 'net.dot.System.Runtime.Tests' terminated with signal 9]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 5/6/2026 2:49:36 PM UTC
Report
Summary
| 24-Hour Hit Count |
7-Day Hit Count |
1-Month Count |
| 70 |
72 |
72 |
Build Information
Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1409132
Build error leg or test failing: System.Runtime.Tests.WorkItemExecution
Pull request: #127503
Error Message
DO NOT USE JSON BELOW IF THIS IS A BUILD BREAK otherwise build analysis will allow pull requests to merge that break the build worse. For a build break, do not use this issue form. Make a regular new issue.
Fill the error message using step by step known issues guidance.
{ "ErrorMessage": "The app 'net.dot.System.Runtime.Tests' terminated with signal 9", "BuildRetry": false, "ExcludeConsoleLog": false }System logs for the run contain the following lines:
Copilot's analysis of the logs
the cause is a code-signing failure.
Test log evidence
Device system log (device-DNCENGOSX118-...log) — the smoking gun The kernel killed the process for a code-signing reason, not OOM:
codesigning / invalid-page means the kernel tried to validate a page of the app's mach-o at runtime and found a hash mismatch against the embedded code signature — the kernel responds with SIGKILL. (Note: jetsam priority was just set to 100 with a 2098 MB soft limit; no jetsam/memorystatus kill events appear for pid 27597.)
Mac host system log (macos.system.log) — the likely upstream cause A few seconds before the launch, the host ran codesign and trust evaluation produced repeated failures:
CSSMERR_TP_NOT_TRUSTEDmeans the signing identity's trust chain didn't validate during the (re)sign step. Combined with the device-side invalid-page exit, this strongly points to the app being signed with an untrusted/broken signing identity (or the resign step producing a corrupt signature), so the iOS kernel rejected pages of the binary as soon as they were paged in and killed the process.Bottom line: The test wasn't killed for memory or test-runner reasons. It was killed by the iOS kernel's code-signing enforcement (
OS_REASON_CODESIGNING/ invalid-page), most likely caused by the failing/untrusted codesign step seen on the Mac host (CSSMERR_TP_NOT_TRUSTED) right before the launch. Fixing the signing identity / provisioning on the Mac should resolve it.Known issue validation
Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1409132
Error message validated:
[The app 'net.dot.System.Runtime.Tests' terminated with signal 9]Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 5/6/2026 2:49:36 PM UTC
Report
Summary