[crash] Fix a rare crash on shutdown due to MidiInput / CriticalSection destruction order

emezeske · June 9, 2026, 3:44pm

Here’s a PR to fix this crash. Details in the PR.

github.com/juce-framework/JUCE

Fix a rare crash on shutdown due to MidiInput / CriticalSection destruction order (#1669)

develop ← emezeske:midi-input-fix

opened 03:43PM - 09 Jun 26 UTC

emezeske

+1 -0

This crash presents as: > EXCEPTION_ACCESS_VIOLATION_WRITE / 0x24: Fatal Erro…r: EXCEPTION_ACCESS_VIOLATION_WRITE / 0x24 > ?, in RtlpWaitOnCriticalSection > ?, in RtlpEnterCriticalSectionContended > ?, in RtlEnterCriticalSection > ?, in juce::AudioDeviceManager::CallbackHandler::handleIncomingMidiMessage > ?, in `juce::MidiInput::Impl::consume'::`8'::<T>::operator() > ... > (20 additional frame(s) were not displayed) It's due to the order in which `enabledMidiInputs` and `midiCallbackLock` are declared in the header: `midiCallbackLock` is destroyed *before* `enabledMidiInputs`. So the midi input callback can race and access the already-destroyed CriticalSection, causing this crash.

Topic		Replies	Views
Crash on shutdown... midi thread? General JUCE discussion	0	347	June 16, 2009
Crash on MIDI input, appears after 'Added support for ID-based MIDI devices' commit (09ebd1d257614571c47af0d08a5f90ba01a7f5c0) General JUCE discussion	2	632	March 6, 2019
Crash on exit where MIDI data was processed while DeviceManager was destroyed General JUCE discussion	3	791	September 21, 2016
MIDI input - crash - and solution! Windows	0	393	January 24, 2008
[fixed] Crash when calling MidiInput::getDevices() Audio Plugins	3	577	February 27, 2017

[crash] Fix a rare crash on shutdown due to MidiInput / CriticalSection destruction order

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[crash] Fix a rare crash on shutdown due to MidiInput / CriticalSection destruction order

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