QThread ASSERT failure in QMutexLocker: “QMutex pointer is misaligned”,

Question

Im trying to create an uploader that will create new threads and in every thread I have a QNetworkAccessManager. All the uploader threads have a reference to a shared list and w

Answer 1

The error you are receiving

ASSERT failure in QMutexLocker: "QMutex pointer is misaligned"

occurs on creation of a QMutexLocker object if the QMutex object passed to the constructor is not aligned on a 2-byte boundary in RAM (in Qt 4.7.1 at least).

The QMutexLocker object uses one member variable to represent both the location of the mutex in memory and its state (whether it is locked or not). The state is represented by the least significant bit of the variable, while the least significant bit of the mutex pointer is assumed to be zero. If this bit is not zero, the ASSERT exception above is thrown.

The only reason for misalignment of the QMutex pointer I can think of is a memory leak or corruption. Check whether you destroy all memory that you allocate (especially in loops) and check all typecasts (you might have casted a pointer of a smaller type to a pointer of a bigger type, damaging memory) and null-terminated strings (which will damage memory if not properly terminated). Finally, verify the thread safety of all memory that you share across threads.