[Qt-interest] Aborting QNetworkReply::post() causes crash

[Info]

Hi Markus,

I'm running a patched version of 4.5.3 (I spoke to you on the qtcentre  
forum earlier today about the patch). I am just building the latest  
4.6 to see if the issue is solved there.

In the meantime the backtrace is:

QtNetworkd4.dll!QHttpNetworkReply::d_func()  Line 146 + 0xa bytes   C++
QtNetworkd4.dll!QHttpNetworkConnectionPrivate::sendRequest 
(QAbstractSocket * socket=0x01947210)  Line 395 + 0x15 bytes  C++
QtNetworkd4.dll!QHttpNetworkConnectionPrivate::_q_encryptedBytesWritten 
(__int64 bytes=16421)  Line 1374 C++
QtNetworkd4.dll!QHttpNetworkConnection::qt_metacall(QMetaObject::Call  
_c=InvokeMetaMethod, int _id=19, void * * _a=0x0160d96c)  Line 132    C 
++
QtCored4.dll!QMetaObject::activate(QObject * sender=0x01947210, int  
from_signal_index=27, int to_signal_index=27, void * *  
argv=0x0160d96c)  Line 3104 + 0x2b bytes C++
QtCored4.dll!QMetaObject::activate(QObject * sender=0x01947210, const  
QMetaObject * m=0x640e5ba8, int local_signal_index=4, void * *  
argv=0x0160d96c)  Line 3178 + 0x15 bytes   C++
QtNetworkd4.dll!QSslSocket::encryptedBytesWritten(__int64 _t1=16421)   
Line 155 + 0x15 bytes C++
QtNetworkd4.dll!QSslSocketPrivate::_q_bytesWrittenSlot(__int64  
written=16421)  Line 2034    C++
QtNetworkd4.dll!QSslSocket::qt_metacall(QMetaObject::Call  
_c=InvokeMetaMethod, int _id=16, void * * _a=0x0160da84)  Line 115 +  
0x1c bytes   C++
QtCored4.dll!QMetaObject::activate(QObject * sender=0x019901b0, int  
from_signal_index=5, int to_signal_index=5, void * * argv=0x0160da84)   
Line 3104 + 0x2b bytes   C++
QtCored4.dll!QMetaObject::activate(QObject * sender=0x019901b0, const  
QMetaObject * m=0x672b1d38, int local_signal_index=1, void * *  
argv=0x0160da84)  Line 3178 + 0x15 bytes   C++
QtCored4.dll!QIODevice::bytesWritten(__int64 _t1=16421)  Line 92 +  
0x14 bytes   C++
QtNetworkd4.dll!QAbstractSocketPrivate::flush()  Line 730   C++
QtNetworkd4.dll!QAbstractSocketPrivate::canWriteNotification()  Line  
650    C++
QtNetworkd4.dll!QAbstractSocketPrivate::writeNotification()  Line 78 +  
0x15 bytes   C++
QtNetworkd4.dll!QAbstractSocketEngine::writeNotification()  Line  
161    C++
QtNetworkd4.dll!QWriteNotifier::event(QEvent * e=0x0160ded4)  Line  
1069 C++
QtGuid4.dll!QApplicationPrivate::notify_helper(QObject *  
receiver=0x01ae7460, QEvent * e=0x0160ded4)  Line 4065 + 0x11 bytes     
C++
QtGuid4.dll!QApplication::notify(QObject * receiver=0x01ae7460, QEvent  
* e=0x0160ded4)  Line 3605 + 0x10 bytes  C++
QtCored4.dll!QCoreApplication::notifyInternal(QObject *  
receiver=0x01ae7460, QEvent * event=0x0160ded4)  Line 610 + 0x15  
bytes  C++
QtCored4.dll!QCoreApplication::sendEvent(QObject *  
receiver=0x01ae7460, QEvent * event=0x0160ded4)  Line 213 + 0x39  
bytes   C++
QtCored4.dll!qt_internal_proc(HWND__ * hwnd=0x005503ca, unsigned int  
message=1024, unsigned int wp=7220, long lp=2)  Line 466 + 0xf bytes    
C++
user32.dll!_InternalCallWinProc at 20()  + 0x28 bytes
user32.dll!_UserCallWinProcCheckWow at 32()  + 0xb7 bytes
user32.dll!_DispatchMessageWorker at 8()  + 0xdc bytes
user32.dll!_DispatchMessageW at 4()  + 0xf bytes
QtCored4.dll!QEventDispatcherWin32::processEvents(QFlags<enum  
QEventLoop::ProcessEventsFlag> flags={...})  Line 751 + 0x17 bytes    C 
++
QtCored4.dll!QEventLoop::processEvents(QFlags<enum  
QEventLoop::ProcessEventsFlag> flags={...})  Line 150    C++
QtCored4.dll!QEventLoop::exec(QFlags<enum  
QEventLoop::ProcessEventsFlag> flags={...})  Line 201 + 0x2d bytes    C 
++
QtCored4.dll!QThread::exec()  Line 487 + 0x15 bytes C++
NetworkTest.exe!NetworkTest::run()  Line 29 C++
QtCored4.dll!QThreadPrivate::start(void * arg=0x00c53520)  Line 309 C++
msvcr80d.dll!_callthreadstartex()  Line 348 + 0xf bytes C
msvcr80d.dll!_threadstartex(void * ptd=0x00cfcef8)  Line 331    C
kernel32.dll!_BaseThreadStart at 8()  + 0x37 bytes


On 6 Nov 2009, at 10:34, Markus Goetz wrote:

> Hi,
>
> ext Info wrote:
>> I've come across an issue when aborting a POST operation which  
>> seems to cause a crash every time:
>>
>> QNetworkReply *reply = m_Manager.post(request, data); // m_Manager  
>> is a QNetworkAccessManager
>>
>> Now, in the same event loop, I call:
>>
>> reply->abort();
>>
>> And in the finished(QNetworkReply*) slot I have a single call:
>>
>> reply->deleteLater();
>>
>> Every time this leads to a crash, the offending line is in  
>> qhttpnetworkreply_p.h, line 146. The 'this' pointer is 0x00000000,  
>> so it seems the deleteLater() call is deleting the QNetworkReply  
>> before the final bytesWritten() slot is triggered.
>>
>> What would cause this to happen? Should I be calling deleteLater()  
>> in the finished() slot? The documentation suggests it and states  
>> that there will be no more updates to the reply's data or metadata  
>> but it seems it is still trying to read from the post input device  
>> after the finished() event.
> Which Qt version?
> Do you have a full backtrace?
>
> Thanks,
> Markus
>

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