Problem with disassembler and SIGILL signal

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

Amaury

Hi there ,

after a day of research I finnaly didn't found what's the real problem .

I read that the return a.exec() Will execute only when a signal is send to it ( when nothing is shown).

I maybe found a track that leads to my destructors , I have some sql request and QUrl posts in my program , ido I need to delete them in the destructor , would that cause a problem if the program is executed during a long time ?

Everything is compiling fine and my program is running well but after a period of time it's crashing.

Finally I was thinking about the SIGILL signal ,when I F10 or F11 on this it's running this part of the program but if it's closing everything on the app would it be normal to have this signal ?

don't know if I was clear ...

mrjj

Hi
SIGILL is not normal.
From normal program errors you do not get this in any easy way.
So the big question is. Can you can get SIGILL from a normal GUI program or
only when using your full code?

It might be some sort of corruption but impossible to guess at :)

Amaury

I didn't tried that but it works with another program I don't have any SIGILL error ...

the problem with this is that I have something like 18 pages and 500 lines by pages on average.

So that said to find out where the problem is do I have to check each lines of my program ? :/

mrjj

@Amaury
Well if ONLY this program does it. Its not compiler.
But you should be really clear about it.
Else you can waste tons of time.

So yes, if it is program error in your code. You will need to find the actual line/the bug.

You can try http://valgrind.org/ but its takes time to use and understand.

Amaury

Thanks for the support , I need to debug my program before I continue so I prefer to waste little time to understand and use the program.
I can't try to debug the code line per line it would take too long and it should be everywhere .

At least when I'm done with it I finally have to find a solution to start my app on boot but for now if it crashes all the time it's not really usefull.

mrjj

@Amaury
Well u should look for array copy. dangling pointers.
old char * types and stuff like that.
To get SIGILL from program bug , you must corrupt
something in the code segment.
Easy way is to use dangling pointer.

So maybe you can guess at functions where it might happen.

Amaury

@mrjj
Well right now you're talking to me in japanese ^^
I'm going to have a look on that didn't had time yesterday , I think I can be helped for one thing or two :)
I'll come back if my problem is solve or not.

mrjj

@Amaury

Oh :) sorry.
What i mean is SIGILL means "what the hell is that instruction" from the cpu.
This can happen if compiler setting is slightly off for target.
OR
you can also have it happen if you write over the end of an array
or use a pointer that is not set.
Like
MyClass *c1; /// dangling pointer
c1->somfunc()
Then when CPU tries to run the func it sees some random garbage at that location
and might say SIGILL.

Amaury

Alright that's clearer ^^
So if I need to create a dangling pointer where do I need to declare it ?
into the class itself ?