Fixed crash in tst_qglthreads.

QGLTextureCache has a read write locker to protect texture lookups.
However, even calling QCache::object() might modify the cache, causing
race conditions, since it modifies the priority order of the objects in
the cache. Therefore, we need to protect it with a QWriteLocker instead
of a QReadLocker.

Task-number: QTBUG-22560
Change-Id: I46fffc624ace27e25fb100f865e1df0a19b9093d
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index 58f6a94..7154545 100644 (file)
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -504,7 +504,7 @@ int QGLTextureCache::maxCost()
 
 QGLTexture* QGLTextureCache::getTexture(QGLContext *ctx, qint64 key)
 {
-    QReadLocker locker(&m_lock);
+    QWriteLocker locker(&m_lock);
     const QGLTextureCacheKey cacheKey = {key, QGLContextPrivate::contextGroup(ctx)};
     return m_cache.object(cacheKey);
 }