SIGSEGV Segmentation Fault after connectToHostEncrypted

KapitanF

Hello, help me! I have QT 5.91 Community and after compile/run is application terminated with error SIGSEGV Segmentation Fault after socket->connectToHostEncrypted(host,port). Linux 64bit GCC 7.1.1 . I mean application is OK. OPENSSL is last version 1.0.2. Here is Backtrace output:

[0_1502507131850_bt1.txt](Uploading 100%)

Here is Disassembler output:

[0_1502507221478_DisAssembler.asm](Uploading 100%)

CPP:

[0_1502507242750_qtsslreceiver.cpp](Uploading 100%)

HEADER:

[0_1502507264725_qtsslreceiver.h](Uploading 100%)

mrjj

Hi
One thing that i noted.
you define
QSslSocket *msocket;
but do not set to nullptr
and then use it later


void QtSslReceiver::OnConnect(const QString &hostname,unsigned short port)
{
    if (!msocket) <<<< Might not be null, might be random value here
    {
        msocket = new QSslSocket(this);
    xx
    }

    msocket->ignoreSslErrors(); <<< Might crash here

To check if that
just try
msocket=nullptr; ( or set it to null in .h)
OnConnect("kapitanf.ddns.net", 5000);

Thats stops it crashing here when i run it.

SGaist

Hi and welcome to devnet,

That doesn't help much, you seem to be trying to show the stack trace of a release build of your application. You should rather start it in debug mode with a debug build.

KapitanF

Hi, SGaist, thank you for Reply. And here is the problem. I am trying debugging and it behaves like Release. QtCreator say in Debug mode:

Starting /home/freefilip/build-QtSslReceiver-Unnamed-Debug/QtSslReceiver...
The program has unexpectedly finished.
/home/freefilip/build-QtSslReceiver-Unnamed-Debug/QtSslReceiver crashed.

I dont know, where is my fail? Debug will detect nothing. Compiler compile my application without problems, BUT after running application program generate error SIGSEGV.

SGaist

Can you show your .pro file ?

Which Linux distribution are you using ?
Which version of GDB ?

KapitanF

Debugger is:
GNU gdb (GDB) Fedora 8.0-20.fc26

OS:
Fedora 26 (last update kernel 4.11.11-300)

Here is .pro file:
[0_1502664502899_QtSslReceiver.pro](Uploading 100%)

KapitanF

Some other ideas?

mrjj

@KapitanF

Hi
All we see it
[0_1502664502899_QtSslReceiver.pro](Uploading 100%)

Do you see real images?

KapitanF

No ,i see only [0_1502664502899_QtSslReceiver.pro](Uploading 100%), i not see real images.

karlheinzreichel

To localize the problem it could be a good idea to use the qt-libraries with symbols (debug version of qt-build)

KapitanF

Hi Karl, thanks for Reply, where i find the debug version of qt-build?

KapitanF

All needed QT files installed on my OS. I know, Debug not work only on my application! Is it SIGNAL from kernel OS, which raise exception SIGSEGV, or is it application compile/dynamic linker error. Is problem in QMAKE, GCC, GDB or CMAKE?

KapitanF

Any ideas?

mrjj

@KapitanF
since none of the images or code is shown, it hard to guess at anything. :)

KapitanF

Ok i understand. I have not permissions to Drag and Drop! Ho i enable it?

KapitanF

main.cpp : https://pastebin.com/cPjTKygq
qtsslreceiver.cpp : https://pastebin.com/dEtj6E7n
qtsslreceiver.h : https://pastebin.com/TzcktAay
qtsslreceiver.pro : https://pastebin.com/KujH0e8k
qtsslreceiver.ui : https://pastebin.com/kLxVkFxE

I dont know, how enable Drag and Drop for this forum.

mrjj

Hi
One thing that i noted.
you define
QSslSocket *msocket;
but do not set to nullptr
and then use it later


void QtSslReceiver::OnConnect(const QString &hostname,unsigned short port)
{
    if (!msocket) <<<< Might not be null, might be random value here
    {
        msocket = new QSslSocket(this);
    xx
    }

    msocket->ignoreSslErrors(); <<< Might crash here

To check if that
just try
msocket=nullptr; ( or set it to null in .h)
OnConnect("kapitanf.ddns.net", 5000);

Thats stops it crashing here when i run it.

KapitanF

Hi mrjj, thank you for Solution. Now application work right. THANK you very much.

mrjj

Oh super . it was only that. the revenge of the uninitialized variable. ;)