Problem with disassembler and SIGILL signal

mrjj

Hi
I dont like the look of
a.installTranslator(&qtTranslator);
Since you give it address of a local variable.
So if it thinks it owns the translator ( as expects a pointer) then it will be double deleted by
"a" and by running out of scope. (after .exe())

Could you try to new it and see if it still crashes?

update:
Hmm Docs dont say it owns it.

Amaury

I have to say that I found this piece of code and just add it to my program since I had some pop-ups written in english ( I'm french).

So is something like this that you mean by new it ? :

QTranslator *qtTranslator = new QTranslator;
      qtTranslator.load(
              "qt_" + QLocale::system().name(),
              QLibraryInfo::location(QLibraryInfo::TranslationsPath)
              );
      a.installTranslator(&qtTranslator);

   return a.exec();

because I can't even copile like this ...

mrjj

hi
yes
except now its pointer, u must get rid of &
a.installTranslator(qtTranslator);

Amaury

That's compiling but when I'm debugging it's still crashing at the same point ...

kshegunov

SIGILL is very unusual, it often means the binary is corrupt (it's the illegal instruction signal). What compiler are you using?
As for @mrjj's suggestion, you can still create on the stack, but do unregister the translator before returning from main(), e.g.:

int main()
{
    // ...
    QTranslator qtTranslator;
    qtTranslator.load("qt_" + QLocale::system().name(), QLibraryInfo::location(QLibraryInfo::TranslationsPath));
    a.installTranslator(&qtTranslator);

    int retcode = a.exec();
    a.removeTranslator(&qtTranslator);

    return retcode;
}

Amaury

I am using Gdb as debugger and Gcc as a compiler , I forget to precise that I was on a raspberry Pi 3.
I would try your way and come back again.

mrjj

@Amaury
Hi
Ok. it was not the translator it seems.

Do you have global object or anything else that might run out of scope and be deleted twice?
You should try putting break point in mainwindow destructor and see if it gets to that part.

Amaury

I have a .h and .cpp named global Where I put 2 global variables as extern. Maybe it's the problem I'm Setting a point break on the Main window and sending you my global.h and global .cpp

Global.h

#ifndef GLOBAL_H
#define GLOBAL_H

#include <QString>

QT_BEGIN_NAMESPACE
class QString;
QT_END_NAMESPACE

extern QString OnlinePath;
extern int Var;


#endif // GLOBAL_H

Global.cpp

`#include "global.h"
#include <QString>


QString OnlinePath= "http://192.168.1.242/app.php/api/smartdevice";
int Var = 0;


``

kshegunov

Are you sure that this compiler produces binaries for that particular instruction set? Look up the compatibility of your gcc version with the instruction set of that particular Pi.

mrjj

Hmm dont seems like it as just a Qstring.
Its more if you have a widget and assign parent.
Then both scope and parent might delete it and it might crash.

Dont the call stack give hint what it was doing ?

Amaury

@kshegunov Sorry I didn't understand anything I'm not really used with the debuggers.

@mrjj Hum I am associating widgets to a parent when using a QStackWidget for example I got my main window with some widgets in it. It the main ui of my application.

I am adding some widgets in a QStackedWidget on the MainWindow and calling them by using their names .

MainWindow

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
    ui(new Ui::MainWindow)
{

    //this->setWindowFlags(Qt::FramelessWindowHint);

    ui->setupUi(this);
    this->move(this->x(),this->y());

    AccueilWindow = new Accueil(this,"AccueilWindow");
    ui->stackedWidget->addWidget(AccueilWindow);

ui->stackedWidget->setCurrentWidget(AccueilWindow);

connect(this,SIGNAL(changeInterface(QString)),this,SLOT(changeOnglet(QString)));
}

void MainWindow::changeOnglet(QString name)
{
    qDebug()<<name;
    if ((name == AccueilWindow->objectName())&&AccueilWindow)
    {
        ui->stackedWidget->setCurrentWidget(AccueilWindow);
        hide_full_ui();
        show_ui();
        return;
    }
    else if ((name == AlarmesWindow->objectName())&&AlarmesWindow)
    {
        ui->stackedWidget->setCurrentWidget(AlarmesWindow);
        show_ui();
        return;
    }
}

Mainwindow.h

private:
    
    Ui::MainWindow *ui;

    Accueil *AccueilWindow;
    Alarmes *AlarmesWindow;

The alarm.cpp

Alarmes::Alarmes(QWidget *parent,QString AlarmesWindow) :
    QWidget(parent),
    Alrm_ui(new Ui::Alarmes)
{
    Alrm_ui->setupUi(this);


    this->setObjectName(AlarmesWindow);
    connect(this,SIGNAL(changeInterface(QString)),qobject_cast<MainWindow *>(parent),SLOT(changeOnglet(QString)));
}

alarm.h

namespace Ui {
class Alarmes;
}

class Alarmes : public QWidget
{
    Q_OBJECT

public:
    explicit Alarmes(QWidget *parent ,QString AlarmesWindow);
    virtual ~Alarmes();

mrjj

Hi
Nothing springs to eye. Seems you let the Qt system handle it.

If you create a default Widgets project and run it on the pi.

Does that also crash at close?

Amaury

If i delete the whole Qtranslator thing it seems that's not ceashing anymore , there just a message saying starting the debug and debug ended. I assume that's ok ...

I didn't tried to let some other programm running to see if there's something but I didn't found any problems on an other application .

Edit : It seems that other programs have no problem ..

And I don't have any more troubles if my main.cpp is like :

int main(int argc, char *argv[])
{
    QTextCodec::setCodecForCStrings(QTextCodec::codecForName("UTF-8"));
    QTextCodec::setCodecForTr(QTextCodec::codecForName("UTF-8"));

    QApplication a(argc, argv);

//    QTranslator qtTranslator;
//        qtTranslator.load("qt_" + QLocale::system().name(), QLibraryInfo::location(QLibraryInfo::TranslationsPath));
//        a.installTranslator(&qtTranslator);





    MainWindow w;
    w.show();

    MemTampon::Db.aff_Temperature();
    MemTampon::Db.aff_Humidite();
    MemTampon::Db.aff_Puissance();
    MemTampon::Db.aff_Nom_SD();


//    a.removeTranslator(&qtTranslator);
    return a.exec();
}

mrjj

Ok
Im not sure what to conclude from that :)
But seems to be related to it anyway then.

Amaury

Yes I'm really not sure about it that's really pointing on this but don't know what's wrong ...

I think I'm going to create some buttons that are written in my language instead of using the Qt popup default buttons.

Thanks for help I'm closing this subject and put it as solved .

See you in a close future I think ^^

Edit Seems to be the return a.exec() that is bugged don't know why ^^

mrjj

@Amaury said in Problem with disassembler and SIGILL signal:

Edit Seems to be the return a.exec() that is bugged don't know why ^^

For QApplication it has setting that says When last window closed,
exit the event loop ( exec() ) and die.
see
app.setQuitOnLastWindowClosed(true);
This is in effect sort of the same as
app.connect(&app, SIGNAL(lastWindowClosed()), &app, SLOT(quit()));

So if some sort of instruction that gets called when deconstructing then it will
show exec() as the the point of crash.

SGaist

Hi,

Out of curiosity, why are you removing the translator before starting the event loop ? Doing it like that raises the following question: why set a translator in the first place ?

Amaury

@SGaist I am removing the translator because it looked like that was this function that send the SIGILL signal .
After all it seems that it doesn't changed anything, but I do need it , just that I can translate my pop-ups in a different way.

@mrjj I'm going to look those potential solutions and post here if I get the answer.

kshegunov

@Amaury
It'd be helpful if you also extract the assembly (a few lines) from the point of the crash, where you get the SIGILL.

Amaury

Those are the first 15 lines of the disassembler where I get my Sigill signal : it happens on line 6

0x6f6a2dd4                   00 00 00 00  andeq	r0, r0, r0
0x6f6a2dd8                   00 00 00 00  andeq	r0, r0, r0
0x6f6a2ddc                   00 00 00 00  andeq	r0, r0, r0
0x6f6a2de0                   fe e1 6e f2  vorr	q15, q15, q15
0x6f6a2de4                   1e ff 2f e1  bx	lr
0x6f6a2de8                   1d 0f 19 ee  mrc	15, 0, r0, cr9, cr13, {0}
0x6f6a2dec                   1e ff 2f e1  bx	lr
0x6f6a2df0                   9f 2f 90 e1  ldrex	r2, [r0]
0x6f6a2df4                   01 30 82 e0  add	r3, r2, r1
0x6f6a2df8                   93 2f 80 e1  strex	r2, r3, [r0]
0x6f6a2dfc                   00 00 52 e3  cmp	r2, #0
0x6f6a2e00                   fa ff ff 1a  bne	0x6f6a2df0
0x6f6a2e04                   03 00 a0 e1  mov	r0, r3
0x6f6a2e08                   1e ff 2f e1  bx	lr
        Function: OPENSSL_cleanse