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Fix QVector detaching in one thread while another destroys it.

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The patch adds handling for a case when a QVector is shared between two
threads. In such scenario detaching in one thread could collide with
destruction in the other one, causing a memory leak or assert in debug
mode.

Task-number: QTBUG-29134
Change-Id: Idbff250d9cfc6cf83174954ea91dbf41f8ea4aa4
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Jędrzej Nowacki 2013-02-12 14:08:48 +01:00 committed by The Qt Project
parent d3a4230757
commit dacc222d5a
2 changed files with 78 additions and 3 deletions
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3
src/corelib/tools/qvector.h
View File

@ -506,8 +506,7 @@ void QVector<T>::reallocData(const int asize, const int aalloc, QArrayData::Allo
}
if (d != x) {
if (!d->ref.deref()) {
Q_ASSERT(!isShared);
if (QTypeInfo<T>::isStatic || !aalloc) {
if (QTypeInfo<T>::isStatic || !aalloc || (isShared && QTypeInfo<T>::isComplex)) {
// data was copy constructed, we need to call destructors
// or if !alloc we did nothing to the old 'd'.
freeData(d);

78
tests/auto/corelib/tools/qvector/tst_qvector.cpp
View File

@ -41,6 +41,8 @@
#include <QtTest/QtTest>
#include <QAtomicInt>
#include <QThread>
#include <QSemaphore>
#include <qvector.h>
struct Movable {
@ -272,6 +274,9 @@ private slots:
void detachInt() const;
void detachMovable() const;
void detachCustom() const;
void detachThreadSafetyInt() const;
void detachThreadSafetyMovable() const;
void detachThreadSafetyCustom() const;
private:
template<typename T> void copyConstructor() const;
@ -295,6 +300,7 @@ private:
template<typename T> void setSharable_data() const;
template<typename T> void setSharable() const;
template<typename T> void detach() const;
template<typename T> void detachThreadSafety() const;
};
@ -2213,5 +2219,75 @@ void tst_QVector::detachCustom() const
QCOMPARE(instancesCount, Custom::counter.loadAcquire());
}
QTEST_APPLESS_MAIN(tst_QVector)
static QAtomicPointer<QVector<int> > detachThreadSafetyDataInt;
static QAtomicPointer<QVector<Movable> > detachThreadSafetyDataMovable;
static QAtomicPointer<QVector<Custom> > detachThreadSafetyDataCustom;
template<typename T> QAtomicPointer<QVector<T> > *detachThreadSafetyData();
template<> QAtomicPointer<QVector<int> > *detachThreadSafetyData() { return &detachThreadSafetyDataInt; }
template<> QAtomicPointer<QVector<Movable> > *detachThreadSafetyData() { return &detachThreadSafetyDataMovable; }
template<> QAtomicPointer<QVector<Custom> > *detachThreadSafetyData() { return &detachThreadSafetyDataCustom; }
static QSemaphore detachThreadSafetyLock;
template<typename T>
void tst_QVector::detachThreadSafety() const
{
delete detachThreadSafetyData<T>()->fetchAndStoreOrdered(new QVector<T>(SimpleValue<T>::vector(400)));
static const uint threadsCount = 5;
struct : QThread {
void run() Q_DECL_OVERRIDE
{
QVector<T> copy(*detachThreadSafetyData<T>()->load());
QVERIFY(!copy.isDetached());
detachThreadSafetyLock.release();
detachThreadSafetyLock.acquire(100);
copy.detach();
}
} threads[threadsCount];
for (uint i = 0; i < threadsCount; ++i)
threads[i].start();
QThread::yieldCurrentThread();
detachThreadSafetyLock.acquire(threadsCount);
// destroy static original data
delete detachThreadSafetyData<T>()->fetchAndStoreOrdered(0);
QVERIFY(threadsCount < 100);
detachThreadSafetyLock.release(threadsCount * 100);
QThread::yieldCurrentThread();
for (uint i = 0; i < threadsCount; ++i)
threads[i].wait();
}
void tst_QVector::detachThreadSafetyInt() const
{
for (uint i = 0; i < 128; ++i)
detachThreadSafety<int>();
}
void tst_QVector::detachThreadSafetyMovable() const
{
const int instancesCount = Movable::counter.loadAcquire();
for (uint i = 0; i < 128; ++i) {
detachThreadSafety<Movable>();
QCOMPARE(Movable::counter.loadAcquire(), instancesCount);
}
}
void tst_QVector::detachThreadSafetyCustom() const
{
const int instancesCount = Custom::counter.loadAcquire();
for (uint i = 0; i < 128; ++i) {
detachThreadSafety<Custom>();
QCOMPARE(Custom::counter.loadAcquire(), instancesCount);
}
}
QTEST_MAIN(tst_QVector)
#include "tst_qvector.moc"