whytofly
/
qt6-bb10
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix QMutex::tryLock with negative values 

The Linux futex implementation had a Q_ASSERT for positive values, but
the documentation says that negative values should be interpreted as
infinite (equal to lock()).

Test that too.

Change-Id: I2f96a502d672732781e88e49797756ca9a809121
Reviewed-by: David Faure (KDE) <faure@kde.org>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
bb10
Thiago Macieira 2012-12-21 11:41:30 -08:00 committed by The Qt Project
parent 96d06124a1
commit 3adbcb58d5
2 changed files with 53 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/corelib/thread/qmutex_linux.cpp
View File

@ -187,7 +187,7 @@ bool lockInternal_helper(QBasicAtomicPointer<QMutexData> &d_ptr, int timeout = -
struct timespec ts, *pts = 0;
QElapsedTimer elapsedTimer;
checkElapsedTimerIsTrivial();
if (IsTimed) {
if (IsTimed && timeout > 0) {
ts.tv_sec = timeout / 1000;
ts.tv_nsec = (timeout % 1000) * 1000 * 1000;
elapsedTimer.start();
@ -206,7 +206,7 @@ bool lockInternal_helper(QBasicAtomicPointer<QMutexData> &d_ptr, int timeout = -
ts.tv_sec = xtimeout / Q_INT64_C(1000) / 1000 / 1000;
ts.tv_nsec = xtimeout % (Q_INT64_C(1000) * 1000 * 1000);
}
if (IsTimed)
if (IsTimed && timeout > 0)
pts = &ts;
// successfully set the waiting bit, now sleep
@ -232,7 +232,6 @@ void QBasicMutex::lockInternal() Q_DECL_NOTHROW
bool QBasicMutex::lockInternal(int timeout) Q_DECL_NOTHROW
{
Q_ASSERT(!isRecursive());
Q_ASSERT(timeout >= 0);
return lockInternal_helper<true>(d_ptr, timeout);
}

51
tests/auto/corelib/thread/qmutex/tst_qmutex.cpp
View File

@ -57,6 +57,8 @@ private slots:
void stressTest();
void tryLockRace();
void tryLockDeadlock();
void tryLockNegative_data();
void tryLockNegative();
void moreStress();
};
@ -579,6 +581,55 @@ void tst_QMutex::tryLockDeadlock()
QCOMPARE(tryLockDeadlockFailureCount, 0);
}
void tst_QMutex::tryLockNegative_data()
{
QTest::addColumn<int>("timeout");
QTest::newRow("-1") << -1;
QTest::newRow("-2") << -2;
QTest::newRow("INT_MIN/2") << INT_MIN/2;
QTest::newRow("INT_MIN") << INT_MIN;
}
void tst_QMutex::tryLockNegative()
{
// the documentation says tryLock() with a negative number is the same as lock()
struct TrylockThread : QThread {
TrylockThread(QMutex &mut, int timeout)
: mut(mut), timeout(timeout), tryLockResult(-1)
{}
QMutex &mut;
int timeout;
int tryLockResult;
void run() {
tryLockResult = mut.tryLock(timeout);
mut.unlock();
}
};
QFETCH(int, timeout);
QMutex mutex;
TrylockThread thr(mutex, timeout);
QSignalSpy spy(&thr, SIGNAL(started()));
mutex.lock();
thr.start();
// the thread should have stopped in tryLock(), waiting for us to unlock
// the mutex. The following test can be falsely positive due to timing:
// tryLock may still fail but hasn't failed yet. But it certainly cannot be
// a false negative: if wait() returns, tryLock failed.
QVERIFY(!thr.wait(200));
// after we unlock the mutex, the thread should succeed in locking, then
// unlock and exit. Do this before more tests to avoid deadlocking due to
// ~QThread waiting forever on a thread that won't exit.
mutex.unlock();
QCOMPARE(spy.count(), 1);
QVERIFY(thr.wait());
QCOMPARE(thr.tryLockResult, 1);
}
class MoreStressTestThread : public QThread
{