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fix(milesaudiomanager): Prevent undefined behavior when passing atomic storage to the Interlocked functions #3667

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fix(milesaudiomanager): Prevent undefined behavior when passing atomic storage to the Interlocked functions #3667

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1359182
refactor(atomic): Use std::atomic instead of casting storage for the …
CryoTheRenegade Oct 26, 2026
4dd1c01
style(milesaudiomanager): Attach the pointer symbol to the type in ad…
CryoTheRenegade Nov 8, 2026
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5 changes: 2 additions & 3 deletions Core/GameEngineDevice/Include/MilesAudioDevice/MilesAudioManager.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#include "Common/GameAudio.h"
#include "mss/mss.h"
#include "WWLib/mutex.h"
#include "Utility/atomic_adapter.h"

class AudioEventRTS;
class DynamicAudioEventRTS;
Expand Down Expand Up @@ -65,7 +66,7 @@ struct PlayingAudio
RefCountPtr<DynamicAudioEventRTS> m_audioEventRTS;
void *m_file; // The file that was opened to play this
PlayingAudioType m_type;
volatile PlayingStatus m_status; // This member is adjusted by another running thread.
std::atomic<PlayingStatus> m_status; // This member is adjusted by another running thread.
Short m_framesFaded;
Bool m_fade;
volatile Bool m_rerequestOnNextUpdate;
Expand All @@ -92,8 +93,6 @@ struct PlayingAudio
{
return m_status == PS_Playing || m_rerequestOnNextUpdate;
}

static_assert(sizeof(m_status) == sizeof(long), "Must be size of long, because it is used with Interlocked functions");
};

struct ProviderInfo
Expand Down
16 changes: 12 additions & 4 deletions Core/GameEngineDevice/Source/MilesAudioDevice/MilesAudioManager.cpp
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Expand Up @@ -1074,13 +1074,21 @@ void MilesAudioManager::releasePlayingAudio( PlayingAudio *playing )
delete playing;
}

//-------------------------------------------------------------------------------------------------
// Sets the status to 'to' if it is 'from', in one atomic step, and returns the status it had before.
static PlayingStatus advancePlayingStatus( PlayingAudio* playing, PlayingStatus from, PlayingStatus to )
{
playing->m_status.compare_exchange_strong(from, to);
return from;
}

//-------------------------------------------------------------------------------------------------
void MilesAudioManager::stopPlayingAudio( PlayingAudio *playing )
{
// Advance from Playing to Stopping
InterlockedCompareExchange(reinterpret_cast<volatile long*>(&playing->m_status), PS_Stopping, PS_Playing);
advancePlayingStatus(playing, PS_Playing, PS_Stopping);
// Advance from Stopping to Stopped
const long prevStatus = InterlockedCompareExchange(reinterpret_cast<volatile long*>(&playing->m_status), PS_Stopped, PS_Stopping);
const PlayingStatus prevStatus = advancePlayingStatus(playing, PS_Stopping, PS_Stopped);
if (prevStatus != PS_Stopping) {
return;
}
Expand Down Expand Up @@ -1597,7 +1605,7 @@ void MilesAudioManager::notifyOfAudioCompletion( UnsignedInt handle, UnsignedInt
}

// it will be cleaned up on the next frame update
InterlockedCompareExchange(reinterpret_cast<volatile long*>(&playing->m_status), PS_Stopping, PS_Playing);
advancePlayingStatus(playing, PS_Playing, PS_Stopping);
}

//-------------------------------------------------------------------------------------------------
Expand Down Expand Up @@ -2740,7 +2748,7 @@ Bool MilesAudioManager::startNextLoop( PlayingAudio *playing )

if (playing->m_audioEventRTS->getDelay() > MSEC_PER_LOGICFRAME_REAL) {
playing->m_rerequestOnNextUpdate = true;
InterlockedCompareExchange(reinterpret_cast<volatile long*>(&playing->m_status), PS_Stopping, PS_Playing);
advancePlayingStatus(playing, PS_Playing, PS_Stopping);
return true;
}

Expand Down
13 changes: 5 additions & 8 deletions Core/Libraries/Source/WWVegas/WWLib/mpsc_intrusive_queue.h
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Expand Up @@ -18,7 +18,7 @@

#pragma once

#include "Utility/interlocked_adapter.h"
#include "Utility/atomic_adapter.h"

// Lock-free intrusive queue for multiple producer threads and a single consumer thread,
// using the same algorithm as the Win32 InterlockedPushEntrySList/InterlockedFlushSList
Expand All @@ -38,14 +38,12 @@ class MPSCIntrusiveQueue
// head, so its next pointer is never visible while stale.
void Push(T* node)
{
T* head;
T* head = m_head.load();
do
{
head = m_head;
node->next = head;
}
while (InterlockedCompareExchangePointer(
reinterpret_cast<void* volatile*>(&m_head), node, head) != head);
while (!m_head.compare_exchange_weak(head, node));
}

// Detaches all nodes and returns them linked in push order, or null if the queue is
Expand All @@ -54,8 +52,7 @@ class MPSCIntrusiveQueue
// suffer ABA.
T* Flush()
{
T* list = static_cast<T*>(InterlockedExchangePointer(
reinterpret_cast<void* volatile*>(&m_head), nullptr));
T* list = m_head.exchange(nullptr);

// The detached chain is in last-in-first-out order, so reverse it.
T* reversed = nullptr;
Expand All @@ -73,5 +70,5 @@ class MPSCIntrusiveQueue
MPSCIntrusiveQueue(const MPSCIntrusiveQueue&) CPP_11(= delete);
MPSCIntrusiveQueue& operator=(const MPSCIntrusiveQueue&) CPP_11(= delete);

T* volatile m_head;
std::atomic<T*> m_head;
};
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