The InitMemoryMgr method creates the mutex without taking ownership:
 

CommBuffer->ghMutex = CreateMutex(&sa, FALSE, MUTEX_NAME);

 
Then, later in the function, it releases ownership in multiple places although it does not have it:
 

if (CommBuffer->ghEvent == NULL) 
{ 
    if(errco == 0)
        errco = GENERALERRORCODE;

 

    free((char*)lpSharedMemoryName);
    ReleaseMutex(CommBuffer->ghMutex);

...

if(CommBuffer->ghMapFile == NULL || CommBuffer->ghMapFile == INVALID_HANDLE_VALUE) 
{ 
    if(errco == 0)
        errco = GENERALERRORCODE;

 

    free((char*)lpSharedMemoryName);
    ReleaseMutex(CommBuffer->ghMutex);

...
if (CommBuffer->gpBuf == NULL)
{

    if(errco == 0)
        errco = GENERALERRORCODE;

 

    free((char*)lpSharedMemoryName);
    ReleaseMutex(CommBuffer->ghMutex);

...
ReleaseMutex(CommBuffer->ghMutex);
free((char*)lpSharedMemoryName);
return SUCCESS;
 
The Join method does the same thing.