Fix hard crash when toggling ASIO while sending a specific app

Local checkpoint - NOT for public release.

Repro (Ed): in applications send mode with an app being captured, turning the
ASIO driver off hard-crashed the process. No log and no crash-report file were
written - and MixingEngine.DisposeEntry swallows managed exceptions - which points
to a native access violation, not a managed throw.

Cause: the ASIO toggle rebuilds the capture backend (ApplyAsioMode -> ApplyAudioRuntime
-> ApplySendSources), which disposes the live ProcessLoopbackCapture. The old design
released the WASAPI COM objects from the disposing thread while the capture thread
could still be inside a native GetBuffer call - a classic use-after-free / AV.

Fix: the capture thread now owns the ENTIRE COM lifecycle. It activates, runs, and
releases every COM object itself, in its finally, only after the loop has exited.
StopRecording/Dispose merely signal and join (2s) - they never touch the COM objects.
If the thread ever wedges in a native call we leak it rather than free from outside
(a rare bounded leak beats a hard crash). The thread is also explicitly MTA, and
activation moved onto it, so the async-activation callback can't stall the UI thread.
bufferReady is volatile and only disposed once the thread has genuinely exited.

Also: ApplyAsioMode force-sets the WASAPI send-list visibility for the new mode, which
resurrected the loopback-outputs list in applications mode; re-assert ApplySendModeVisibility
at the end so the correct list stays shown after an ASIO toggle.

New self-test "Per-application capture lifecycle" runs real start/stop/dispose cycles
of the native capture against our own process on hardware - a bad teardown would AV
and fail the gate. Gate: 16/16.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

This commit is contained in:

Ednunp

2026-07-12 11:23:18 +01:00

co-authored by

Claude Opus 4.8

parent f8a42f2806

commit ffeba4ad2b

3 changed files with 113 additions and 44 deletions

									
										src/RemSound.App/MainForm.cs
									
		+4
		
												View File
												
				@@ -6566,6 +6566,10 @@ public sealed class MainForm : Form

				        // to re-tick to get audio back.

				        ApplyAudioRuntime();

				        ApplyReceiveDevices();

				        // The block above force-set the WASAPI send-list visibility for the new mode. Re-assert the

				        // per-application send view on top so the loopback-outputs list stays hidden (and the app list

				        // shown) when we're in applications mode — ASIO toggling must not resurrect the wrong list.

				        ApplySendModeVisibility();

				        if (wipedSomething) logFile.Event($"audio mode change wiped now-hidden device ticks");

				    }