Details
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Bug
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Resolution: Unresolved
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P3: Somewhat important
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None
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5.13
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None
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All
Description
When static build version qt framework is link to a program, and
the program create the application procedure like this:
+fun main:
| +fun create_app:
|+ new QApplication
|+ new QWidget
................
|+ fun delete_app:
|- delete QWidget
|- delete QApplication
crash will happen in the delete application part.
When I trace back the crash, I found there are several
incorrect resources clean up code for some static global
variables.
This kind of error happened in this way:
+fun main:
| +fun create_app:
|+ new QApplication(xxxx, xxx)
|+ (1) static variable created
|+ new QWidget(xxxx, xxx)
................
|+ fun delete_app:
|+ delete QWidget
|+ (2) static variable released automatically !!!
|+ delete QApplication
|+ (3) call_res_clean_up_fun_without_check !!!!
For my application, I locate this kind bug in 3 files, and my patch is like this:
diff --git a/src/gui/image/qicon.cpp b/src/gui/image/qicon.cpp index 80fa65daac..0166a06abe 100644 --- a/src/gui/image/qicon.cpp +++ b/src/gui/image/qicon.cpp @@ -121,7 +121,10 @@ Q_GLOBAL_STATIC(IconCache, qtIconCache) static void qt_cleanup_icon_cache() { - qtIconCache()->clear(); + IconCache* cache = qtIconCache(); + if( cache ){ + qtIconCache()->clear(); + } } /*! \internal diff --git a/src/gui/kernel/qtouchdevice.cpp b/src/gui/kernel/qtouchdevice.cpp index 511e92566e..371f2e9326 100644 --- a/src/gui/kernel/qtouchdevice.cpp +++ b/src/gui/kernel/qtouchdevice.cpp @@ -208,8 +208,10 @@ static QBasicMutex devicesMutex; static void cleanupDevicesList() { QMutexLocker lock(&devicesMutex); - qDeleteAll(*deviceList()); - deviceList()->clear(); + if (deviceList()){ + qDeleteAll(*deviceList()); + deviceList()->clear(); + } } /*! diff --git a/src/gui/painting/qbrush.cpp b/src/gui/painting/qbrush.cpp index f56be55325..507d8384da 100644 --- a/src/gui/painting/qbrush.cpp +++ b/src/gui/painting/qbrush.cpp @@ -167,7 +167,9 @@ Q_GLOBAL_STATIC(QBrushPatternImageCache, qt_brushPatternImageCache) static void qt_cleanup_brush_pattern_image_cache() { - qt_brushPatternImageCache()->cleanup(); + if(qt_brushPatternImageCache()) { + qt_brushPatternImageCache()->cleanup(); + } } Q_GUI_EXPORT QImage qt_imageForBrush(int brushStyle, bool invert) diff --git a/src/gui/text/qfontdatabase.cpp b/src/gui/text/qfontdatabase.cpp index fe7dd80e44..58e4ac8cbd 100644 --- a/src/gui/text/qfontdatabase.cpp +++ b/src/gui/text/qfontdatabase.cpp @@ -2620,6 +2620,9 @@ bool QFontDatabase::removeAllApplicationFonts() QMutexLocker locker(fontDatabaseMutex()); QFontDatabasePrivate *db = privateDb(); + if (!db) { + return true; + } if (db->applicationFonts.isEmpty()) return false;
please check it.
thanks a lot!