Fix RTCAudioDeviceModule crash during deallocation by making C++ observer teardown thread-safe#74
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ipavlidakis merged 3 commits intodevelopfrom Feb 26, 2026
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…ardown races When `RTCAudioDeviceModule` is deallocated, its C++ observer/native state can be torn down while audio callbacks or thread shutdown are still in progress, which can lead to `EXC_BAD_ACCESS` during `object_cxxDestruct` in Swift ARC teardown paths. This change makes deallocation safer by: - Capturing `_native`, `_workerThread`, and `_observer` locally before teardown. - Guarding worker-thread teardown work behind `native && workerThread && !IsQuitting()`. - Detaching observer on the worker thread before deleting it. - Avoiding unsafe assumptions about worker-thread availability during object destruction. Build verification: - Ran: `bundle exec fastlane ios build verbose:true zip_product_skip:true root:/Users/ipavlidakis/workspace/webrtc/src skip_licenses:true maccatalyst_support:false` - Result: success
martinmitrevski
approved these changes
Feb 16, 2026
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Description
This change addresses a crash path where AudioDeviceModule.__ivar_destroyer() could crash during app UI teardown / call end because Objective-C++ ivar destruction races with audio-engine lifecycle/worker thread callbacks.
Problem
Crash signature: EXC_BAD_ACCESS in object_cxxDestruct after AudioDeviceModule dealloc.
Triggered during call teardown, while callbacks/release chain from Swift (Call/WebRTCCoordinator) was unwinding.
Root cause
RTCAudioDeviceModule destructor currently removed observer/native linkage and deleted the C++ observer without fully validating thread/teardown state.
If worker thread is gone or quitting, callback paths and object state can become inconsistent.
Fix
In RTCAudioDeviceModule.mm (dealloc), deallocation now:
snapshots native/thread/observer pointers first,
performs detach (SetObserver(nullptr) and observer->delegate_ = nil) only when safe on a non-quitting worker thread,
only then deletes observer state.
avoids unsafe destruction assumptions when thread is unavailable.
Validation
fastlane build command above completes successfully end-to-end.
Notes
No integration-side API changes required.
If consumers perform custom ADM lifecycle mutation, prefer serializing module replacement only after full stop/shutdown flow.