spice-gtk: fix SPICE deadlock under memory pressure - #7853
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AudioOutputUnitStop() called from GStreamer in the main context thread hangs under high memory load (e.g. concurrent LLM usage), causing all SPICE services including video and input to hang while the VM is still running. Short-term fix (this PR): run GStreamer state changes on a separate, serialized worker thread per stream so the hang does not block other SPICE services. Long-term fix?: this appears to require either a fix from Apple or for audio to run in a separate process. Once the connection to CoreAudio is hung, it does not seem to be recoverable by the same process. Assisted-by: Claude:claude-opus-4-8
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Also confirming I read https://github.com/utmapp/UTM/blob/main/CONTRIBUTING.md and as far as I can tell followed it. I used /utm-review but not /utm-submit. |
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The failed check looks like a build timeout and not an issue with the PR. |
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CoreAudio AudioOutputUnitStop() hangs under high memory load (e.g. concurrent LLM usage). GStreamer calls AudioOutputUnitStop() in the main context thread, causing all SPICE services including video and input to hang while the VM is still running.
Short-term fix (this PR): run GStreamer state changes on a separate, serialised worker thread per stream so the hang does not block other SPICE services.
Long-term fix?: this appears to require either a fix from Apple or for audio to run in a separate process. Once the connection to CoreAudio is hung, it does not seem to be recoverable by the same process. FB24659938 opened with Apple.
To reproduce:
Developed with AI but human tested. Before the change, all video, audio, and input hung within a few minutes of running a local LLM, and live process sampling (
sample(1)) found that the main context was hung in AudioOutputUnitStop(). Post-change, audio still hangs but video and input are unaffected, and only the worker is blocked. Test system: macOS 27.0 latest developer beta (26A5425a), UTM 5.0.5 beta.Assisted-by: Claude:claude-opus-4-8