qemu-thread: Assert locks are initialized before using

Not all platforms check whether a lock is initialized before used.  In
particular Linux seems to be more permissive than OSX.

Check initialization state explicitly in our code to catch such bugs
earlier.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170704122325.25634-1-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 33 insertions, 1 deletions

diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
index 653f29f..94f3491 100644
--- a/util/qemu-thread-win32.c
+++ b/util/qemu-thread-win32.c
@@ -46,15 +46,19 @@ static void error_exit(int err, const char *msg)
 void qemu_mutex_init(QemuMutex *mutex)
 {
     InitializeSRWLock(&mutex->lock);
+    mutex->initialized = true;
 }
 
 void qemu_mutex_destroy(QemuMutex *mutex)
 {
+    assert(mutex->initialized);
+    mutex->initialized = false;
     InitializeSRWLock(&mutex->lock);
 }
 
 void qemu_mutex_lock(QemuMutex *mutex)
 {
+    assert(mutex->initialized);
     AcquireSRWLockExclusive(&mutex->lock);
     trace_qemu_mutex_locked(mutex);
 }
@@ -63,6 +67,7 @@ int qemu_mutex_trylock(QemuMutex *mutex)
 {
     int owned;
 
+    assert(mutex->initialized);
     owned = TryAcquireSRWLockExclusive(&mutex->lock);
     if (owned) {
         trace_qemu_mutex_locked(mutex);
@@ -73,6 +78,7 @@ int qemu_mutex_trylock(QemuMutex *mutex)
 
 void qemu_mutex_unlock(QemuMutex *mutex)
 {
+    assert(mutex->initialized);
     trace_qemu_mutex_unlocked(mutex);
     ReleaseSRWLockExclusive(&mutex->lock);
 }
@@ -80,25 +86,31 @@ void qemu_mutex_unlock(QemuMutex *mutex)
 void qemu_rec_mutex_init(QemuRecMutex *mutex)
 {
     InitializeCriticalSection(&mutex->lock);
+    mutex->initialized = true;
 }
 
 void qemu_rec_mutex_destroy(QemuRecMutex *mutex)
 {
+    assert(mutex->initialized);
+    mutex->initialized = false;
     DeleteCriticalSection(&mutex->lock);
 }
 
 void qemu_rec_mutex_lock(QemuRecMutex *mutex)
 {
+    assert(mutex->initialized);
     EnterCriticalSection(&mutex->lock);
 }
 
 int qemu_rec_mutex_trylock(QemuRecMutex *mutex)
 {
+    assert(mutex->initialized);
     return !TryEnterCriticalSection(&mutex->lock);
 }
 
 void qemu_rec_mutex_unlock(QemuRecMutex *mutex)
 {
+    assert(mutex->initialized);
     LeaveCriticalSection(&mutex->lock);
 }
 
@@ -106,25 +118,31 @@ void qemu_cond_init(QemuCond *cond)
 {
     memset(cond, 0, sizeof(*cond));
     InitializeConditionVariable(&cond->var);
+    cond->initialized = true;
 }
 
 void qemu_cond_destroy(QemuCond *cond)
 {
+    assert(cond->initialized);
+    cond->initialized = false;
     InitializeConditionVariable(&cond->var);
 }
 
 void qemu_cond_signal(QemuCond *cond)
 {
+    assert(cond->initialized);
     WakeConditionVariable(&cond->var);
 }
 
 void qemu_cond_broadcast(QemuCond *cond)
 {
+    assert(cond->initialized);
     WakeAllConditionVariable(&cond->var);
 }
 
 void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex)
 {
+    assert(cond->initialized);
     trace_qemu_mutex_unlocked(mutex);
     SleepConditionVariableSRW(&cond->var, &mutex->lock, INFINITE, 0);
     trace_qemu_mutex_locked(mutex);
@@ -134,21 +152,28 @@ void qemu_sem_init(QemuSemaphore *sem, int init)
 {
     /* Manual reset.  */
     sem->sema = CreateSemaphore(NULL, init, LONG_MAX, NULL);
+    sem->initialized = true;
 }
 
 void qemu_sem_destroy(QemuSemaphore *sem)
 {
+    assert(sem->initialized);
+    sem->initialized = false;
     CloseHandle(sem->sema);
 }
 
 void qemu_sem_post(QemuSemaphore *sem)
 {
+    assert(sem->initialized);
     ReleaseSemaphore(sem->sema, 1, NULL);
 }
 
 int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
 {
-    int rc = WaitForSingleObject(sem->sema, ms);
+    int rc;
+
+    assert(sem->initialized);
+    rc = WaitForSingleObject(sem->sema, ms);
     if (rc == WAIT_OBJECT_0) {
         return 0;
     }
@@ -160,6 +185,7 @@ int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
 
 void qemu_sem_wait(QemuSemaphore *sem)
 {
+    assert(sem->initialized);
     if (WaitForSingleObject(sem->sema, INFINITE) != WAIT_OBJECT_0) {
         error_exit(GetLastError(), __func__);
     }
@@ -193,15 +219,19 @@ void qemu_event_init(QemuEvent *ev, bool init)
     /* Manual reset.  */
     ev->event = CreateEvent(NULL, TRUE, TRUE, NULL);
     ev->value = (init ? EV_SET : EV_FREE);
+    ev->initialized = true;
 }
 
 void qemu_event_destroy(QemuEvent *ev)
 {
+    assert(ev->initialized);
+    ev->initialized = false;
     CloseHandle(ev->event);
 }
 
 void qemu_event_set(QemuEvent *ev)
 {
+    assert(ev->initialized);
     /* qemu_event_set has release semantics, but because it *loads*
      * ev->value we need a full memory barrier here.
      */
@@ -218,6 +248,7 @@ void qemu_event_reset(QemuEvent *ev)
 {
     unsigned value;
 
+    assert(ev->initialized);
     value = atomic_read(&ev->value);
     smp_mb_acquire();
     if (value == EV_SET) {
@@ -232,6 +263,7 @@ void qemu_event_wait(QemuEvent *ev)
 {
     unsigned value;
 
+    assert(ev->initialized);
     value = atomic_read(&ev->value);
     smp_mb_acquire();
     if (value != EV_SET) {