Environment:
- macOS 27.0 beta (26A5368g)
- Xcode 27 beta — Instruments 27.0 (64578.226), build 27A5209h
- MacBook Pro (M1, 2020), 16 GB — MacBookPro17,1
- Target: physical iPhone running an iOS app (on-device LLM inference benchmarking)
Summary: Instruments crashes reproducibly with EXC_BREAKPOINT (SIGTRAP) shortly after I stop a recording. Recording itself works — the crash occurs during the post-stop analysis phase, while the trace is being processed. This has happened multiple times today with different templates (Time Profiler, and a custom document with Power Profiler / os_signpost / Thermal State).
Steps to reproduce:
- Open Instruments 27.0 beta, choose Time Profiler (or a document containing Power Profiler + os_signpost)
- Target a physical iPhone and an installed app
- Record for a short period, then press Stop
- Instruments crashes while analyzing/importing the trace
Crash details: The crashing thread is always on the dispatch queue com.apple.dt.frame.activity, inside InstrumentsPlugIn transformer/modeler code. In one report the crashing frame is:
Thread 10 Crashed:: Dispatch queue: com.apple.dt.frame.activity 0 InstrumentsPlugIn NetworkConnectionStatsModeling.__receiveRow(cursor:writer:referenceManager:) + 920 1 InstrumentsPlugIn TransformerExecutionUnit.run(yieldBlock:) + 92 2 InstrumentsPlugIn specialized TransformerHostingModeler.populateOutputTables(_:usingObserverations:parameters:checkToYieldBlock:) + 2344
Exception Type: EXC_BREAKPOINT (SIGTRAP), esr 0xf2000001 (Breakpoint) brk 1
At crash time, sibling worker threads on the same queue were executing SystemPowerImpactModeling and ProcessSubsystemImpactModeling transformers, so the failure appears to be in the modeling pipeline that runs when the recording is finalized.
Incident identifiers from two occurrences today:
- D6D2467F-8553-487C-A291-EC30C0D2846F (14:13 IST)
- 55017CAB-5345-4865-9695-36228B B80AA4A (18:20 IST)
Filed via Feedback Assistant as FBXXXXXXXX with full crash logs and sysdiagnose attached.
Questions:
- Is this a known issue in the current Instruments 27.0 beta?
- Is there a recommended workaround to record and analyze traces until a fix ships — e.g., recording headlessly with xctrace and opening the .trace in a late
r build?
Happy to provide the .trace files or additional diagnostics. Thanks!