[Qt-interest] Help with MacOS Crash Report

[Joshua Grauman]

Hello all,

A customer emailed me a MacOS crash report. I've been unable to reproduce 
the crash, and so was trying to figure out what I could from the report. 
It looks like a seg fault. I guess what follows is a stack trace. Does 
anyone know enough about Qt internals to give me more info? I do have a 
data structure that is a QMap<QString, QPixmap> in my program. Does anyone 
know what could cause QMap<QString, QPixmap>::detach_helper() to segfault? 
Am I reading it correctly that that is what happened? When does 
detach_helper() get called? I'm assuming this is a bug in my program, but 
I guess there is a remote possibility this is a bug in Qt.

Thanks!

Josh


Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x000000011cf7ffff
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   com.yourcompany.ScrollTag     	0x000000010009b9a5 QMap<QString, QPixmap>::detach_helper() + 287621
1   com.yourcompany.ScrollTag     	0x00000001000c6e84 QMap<QString, QPixmap>::detach_helper() + 464996
2   com.yourcompany.ScrollTag     	0x000000010002086e QHash<QChar, char>::detach_helper() + 115662
3   QtCore                        	0x00000001012c02c6 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 710
4   com.yourcompany.ScrollTag     	0x000000010015499d OptionsDialog::~OptionsDialog() + 781
5   QtGui                         	0x000000010064a4cc QWidget::event(QEvent*) + 2844
6   QtGui                         	0x00000001009c079c QFrame::event(QEvent*) + 44
7   QtGui                         	0x00000001009c38fb QLabel::event(QEvent*) + 91
8   QtGui                         	0x00000001005f37cd QApplicationPrivate::notify_helper(QObject*, QEvent*) + 189
9   QtGui                         	0x00000001005fbf40 QApplication::notify(QObject*, QEvent*) + 7776
10  QtCore                        	0x00000001012b997c QCoreApplication::notifyInternal(QObject*, QEvent*) + 124
11  QtGui                         	0x00000001005f3acc QApplication::topLevelWidgets() + 252
12  QtGui                         	0x00000001005a9e19 QMacCocoaAutoReleasePool::~QMacCocoaAutoReleasePool() + 15993
13  com.apple.AppKit              	0x00007fff82c40763 -[NSWindow sendEvent:] + 5409
14  QtGui                         	0x00000001005a194c QMacInputContext::reset() + 33932
15  com.apple.AppKit              	0x00007fff82b75ee2 -[NSApplication sendEvent:] + 4719
16  QtGui                         	0x00000001005a500a QMacInputContext::reset() + 47946
17  com.apple.AppKit              	0x00007fff82b0c922 -[NSApplication run] + 474
18  QtGui                         	0x00000001005aec94 QDesktopWidget::resizeEvent(QResizeEvent*) + 12708
19  QtCore                        	0x0000000101394f14 QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 68
20  QtCore                        	0x0000000101395234 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 180
21  QtCore                        	0x000000010139685c QCoreApplication::exec() + 188
22  com.yourcompany.ScrollTag     	0x0000000100029ca4 QHash<QChar, char>::detach_helper() + 153604
23  com.yourcompany.ScrollTag     	0x0000000100004926 QHash<QChar, char>::detach_helper() + 1158
24  com.yourcompany.ScrollTag     	0x0000000100004845 QHash<QChar, char>::detach_helper() + 933

Thread 1:  Dispatch queue: com.apple.libdispatch-manager
0   libSystem.B.dylib             	0x00007fff8295008a kevent + 10
1   libSystem.B.dylib             	0x00007fff82951f5d _dispatch_mgr_invoke + 154
2   libSystem.B.dylib             	0x00007fff82951c34 _dispatch_queue_invoke + 185
3   libSystem.B.dylib             	0x00007fff8295175e _dispatch_worker_thread2 + 252
4   libSystem.B.dylib             	0x00007fff82951088 _pthread_wqthread + 353
5   libSystem.B.dylib             	0x00007fff82950f25 start_wqthread + 13

Thread 2:
0   libSystem.B.dylib             	0x00007fff8297adce select$DARWIN_EXTSN + 10
1   com.apple.CoreFoundation      	0x00007fff84b3de92 __CFSocketManager + 818
2   libSystem.B.dylib             	0x00007fff82970456 _pthread_start + 331
3   libSystem.B.dylib             	0x00007fff82970309 thread_start + 13

Thread 3:
0   libSystem.B.dylib             	0x00007fff8297adce select$DARWIN_EXTSN + 10
1   QtCore                        	0x0000000101377560 QFSFileEngine::rmdir(QString const&, bool) const + 12816
2   QtCore                        	0x00000001012dc02f QThread::setPriority(QThread::Priority) + 495
3   libSystem.B.dylib             	0x00007fff82970456 _pthread_start + 331
4   libSystem.B.dylib             	0x00007fff82970309 thread_start + 13