memory leak - where?

[SixDegrees]

I've ran it with that options for a while and it says:

LEAK SUMMARY:
definitely lost: 1,792 bytes in 8 blocks
indirectly lost: 8,400 bytes in 418 blocks
possibly lost: 5,756,014 bytes in 7,557 blocks
still reachable: 1,967,661 bytes in 8,582 blocks
suppressed: 0 bytes in 0 blocks

LEAK SUMMARY:
definitely lost: 1,792 bytes in 8 blocks
indirectly lost: 8,400 bytes in 418 blocks
possibly lost: 5,756,014 bytes in 7,557 blocks
still reachable: 1,967,661 bytes in 8,582 blocks
suppressed: 0 bytes in 0 blocks

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Well, it says a good deal more than that. Valgrind gives you a detailed report not only on the total amount of memory leaked, but where it was leaked, right down to the line number. You'll want to compile in debug mode to get the best report, but even without debugging information it's usually possible to track down the portion of code responsible for a leak.

Read through the valgrind documentation so you know what you're looking at.

[Tomasz]

Well, it says a good deal more than that.

Yes, It says really a lot of things. Sometimes it says about errors even in 'clean' application (window only) just created in Qt Creator. I don't have a lot of experience with valgrind, I'm reading documentation but still have no idea how to track that leaks. Code looks fine for me.

thaks in advance
best regards
Tomasz

[wysota]

Sometimes you can get false positives so it's important to understand why certain things are reported. But you should get a very detailed output with a place in code and reason for every leak.

[Tomasz]

Report like this?

==29102== 3,392 bytes in 143 blocks are possibly lost in loss record 371 of 380
==29102==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==29102==    by 0x50146F3: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x5019579: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x501A982: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x5368A54: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x53698A0: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x536ADB0: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x536B969: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x536264B: XML_ParseBuffer (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x50187FA: FcConfigParseAndLoad (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x5018B43: FcConfigParseAndLoad (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x501A038: ??? (in /usr/lib/libfontconfig.so.1.4.4)

==29102== 3,392 bytes in 143 blocks are possibly lost in loss record 371 of 380
==29102==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==29102==    by 0x50146F3: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x5019579: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x501A982: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x5368A54: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x53698A0: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x536ADB0: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x536B969: ??? (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x536264B: XML_ParseBuffer (in /usr/lib/libexpat.so.1.5.2)
==29102==    by 0x50187FA: FcConfigParseAndLoad (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x5018B43: FcConfigParseAndLoad (in /usr/lib/libfontconfig.so.1.4.4)
==29102==    by 0x501A038: ??? (in /usr/lib/libfontconfig.so.1.4.4)

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It's from application where nothing happens - there's only window.

Sorry I'm very stubborn about this memory leak but I've wrote some applications and all of them works fine on PC but on ARM after some time applications starting to work very slow and it looks like everything freezes (especially applications which uses SQLite databases). I suppose It's memory leak (applications are not complicated). Maybe I should look for cause somewhere else?

thanks in advance
best regards
Tomasz

[SixDegrees]

Wait - you suppose it's a memory leak? You're not sure? Why do you think it's a memory leak?

You aren't going to find solutions to your problems unless you describe them correctly. Use a tool like 'top' to monitor your application's memory usage over time, and see if it increases indefinitely. Or if there's some runaway CPU process bogging down the system. Or try netstat if you're connecting to a remote server, to see if there's some aberrant network activity that might be causing the slowdown.

Or, if you're really fixated on believing it's a memory issue, why not simply try destroying the connection you started off suspecting, and see if that makes the problem go away?

Or you can continue to pore over the valgrind output, looking for bytes marked as definitely lost; as you can see, it provides references back to the line in your source code where the problem originated.

[Tomasz]

Use a tool like 'top' to monitor your application's memory usage over time, and see if it increases indefinitely.

I've used 'top' and memory increases all the time the program works. Maybe someone could check my project (it's really short) because I have no idea what I'm doing wrong. I will be really grateful I can only guess it can by connected with databases...

thanks in advance
best regards
Tomasz

[wysota]

Does valgrind report leaks in your code?

[Tomasz]

Yes It reports memory leaks as I said earlier. He reports it's connected with database functions (I'm still learning to use valgrind so I can't say nothing more now) but I know it happens mostly when I'm using functions that are doing something with database... so it would be nice if someone check my whole code because I think I'm doing the same mistake in every app...

thanks in advance
best regards
Tomasz

[wysota]

Yes It reports memory leaks as I said earlier. He reports it's connected with database functions (I'm still learning to use valgrind so I can't say nothing more now) but I know it happens mostly when I'm using functions that are doing something with database... so it would be nice if someone check my whole code because I think I'm doing the same mistake in every app...

Please show us the relevant sections of the report and corresponding lines of your source code.

[Tomasz]

Using valgrind for QT is very difficult. It report about 84000 errors (like "Conditional jump or move depends on uninitialised value(s)"). I really don't know what is important here. I was observing my program and I've noticed that memory is growing while I'm using function in code below.

bool MainWindow::pobierzKomunikaty()
{
    bool ok;
    QTextStream out(stdout);
    QString zapytanie;
    QSqlRecord rec;
    QSqlQueryModel queryModel;
    QSqlQuery query;
    QFont font;
 
    font.setPointSize(7);
 
    odczytanoOstatnieKomunikaty=0;
 
    ok = bdb.open();
 
    if (ok)
    {
        out << endl << "Otworzylem baze!" << endl ;
    } else {
        out << "Nie udalo sie otworzyc bazy!" << endl;
    }
 
    queryModel.clear();
 
    queryModel.setQuery("SELECT * FROM server_notifications WHERE complete='0'", bdb);
 
    liczbaWiadomosci = queryModel.rowCount();
 
    bdb.close();
 
#ifdef DEBUG
    out << "Mamy: " << liczbaWiadomosci << " wiadomosci!" << endl;
#endif
 
 
    for(int i=0 ; i<liczbaWiadomosci; i++)
    {
        rec = queryModel.record(i);
 
 
#ifdef DEBUG
        out << rec.value(1).toString() << ": ";
        out << rec.value(2).toString() << endl;
#endif
 
        QMessageBox *msgBox=new QMessageBox;
 
        if(rec.value(1).toString()=="warning") msgBox->setIcon(QMessageBox::Warning);
        else if (rec.value(1).toString()=="info") msgBox->setIcon(QMessageBox::Information);
        else if (rec.value(1).toString()=="error") msgBox->setIcon(QMessageBox::Critical);
 
        if(rec.value(1).toString()!="confirmation")
        {
                msgBox->setFont(font);
                msgBox->setWindowTitle(rec.value(1).toString());
                msgBox->setText(rec.value(2).toString());
 
                QSpacerItem* horizontalSpacer = new QSpacerItem(240, 290, QSizePolicy::Minimum, QSizePolicy::Minimum);
                QGridLayout* layout = (QGridLayout*)msgBox->layout();
                layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());
 
                msgBox->move(0,0);
                msgBox->exec();
 
                delete msgBox;
 
                ok = bdb.open();
 
                zapytanie.clear();
                zapytanie="update server_notifications set complete='1'";
                zapytanie.append(" where id='");
                zapytanie.append(QString::number(rec.value(0).toInt()));
                zapytanie.append("'");
 
                query.clear();
                query.prepare(zapytanie);
                ok = query.exec();
                query.clear();
 
                bdb.close();
            } else if (rec.value(1).toString()=="confirmation") {
                msgBox->setIcon(QMessageBox::Question);
                msgBox->setFont(font);
                msgBox->setWindowTitle(rec.value(1).toString());
                msgBox->setText(rec.value(2).toString());
                msgBox->setStandardButtons(QMessageBox::Yes | QMessageBox::No);
 
                QSpacerItem* horizontalSpacer = new QSpacerItem(240, 290, QSizePolicy::Minimum, QSizePolicy::Minimum);
                QGridLayout* layout = (QGridLayout*)msgBox->layout();
                layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());
 
                msgBox->move(0,0);
                int result = msgBox->exec();
 
                delete msgBox;
 
                ok = bdb.open();
 
                zapytanie.clear();
                if (result == QMessageBox::Yes) zapytanie="update server_notifications set complete='2'";
                else if (result == QMessageBox::No) zapytanie="update server_notifications set complete='3'";
                zapytanie.append(" where id='");
                zapytanie.append(QString::number(rec.value(0).toInt()));
                zapytanie.append("'");
 
                query.clear();
                query.prepare(zapytanie);
                ok = query.exec();
                query.clear();
 
                bdb.close();
            }
    }
 
    zapytanie.clear();
    rec.clear();
    queryModel.clear();
    odczytanoOstatnieKomunikaty=1;
 
    return ok;
}
 
bool MainWindow::wyswietlKomunikaty()
{
    if(odczytanoOstatnieKomunikaty==0)
    {
 
    } else
    {
        pobierzKomunikaty();
        odczytajNotificationInterval();
        timer.start(notificationInterval);
    }
 
    return 1;
}
 
bool MainWindow::odczytajNotificationInterval()
{
    bool ok;
    QTextStream out(stdout);
    QSqlRecord rec;
    QSqlQueryModel queryModel;
 
    ok = bdb.open();
 
 
    if (ok)
    {
        out << endl << "Otworzylem baze!" << endl ;
    } else {
        out << "Nie udalo sie otworzyc bazy!" << endl;
    }
 
    queryModel.clear();
 
    queryModel.setQuery("SELECT * FROM config WHERE name='qt-notification-interval'", bdb);
 
    rec = queryModel.record(0);
    notificationInterval = (rec.value(1).toInt())*1000;
 
#ifdef DEBUG
    out << "Notification interval: " << notificationInterval << " ms" << endl;
#endif
 
    rec.clear();
    queryModel.clear();
    bdb.close();
 
    return ok;
}

bool MainWindow::pobierzKomunikaty()
{
    bool ok;
    QTextStream out(stdout);
    QString zapytanie;
    QSqlRecord rec;
    QSqlQueryModel queryModel;
    QSqlQuery query;
    QFont font;

    font.setPointSize(7);

    odczytanoOstatnieKomunikaty=0;

    ok = bdb.open();

    if (ok)
    {
        out << endl << "Otworzylem baze!" << endl ;
    } else {
        out << "Nie udalo sie otworzyc bazy!" << endl;
    }

    queryModel.clear();

    queryModel.setQuery("SELECT * FROM server_notifications WHERE complete='0'", bdb);

    liczbaWiadomosci = queryModel.rowCount();

    bdb.close();

#ifdef DEBUG
    out << "Mamy: " << liczbaWiadomosci << " wiadomosci!" << endl;
#endif


    for(int i=0 ; i<liczbaWiadomosci; i++)
    {
        rec = queryModel.record(i);


#ifdef DEBUG
        out << rec.value(1).toString() << ": ";
        out << rec.value(2).toString() << endl;
#endif

        QMessageBox *msgBox=new QMessageBox;

        if(rec.value(1).toString()=="warning") msgBox->setIcon(QMessageBox::Warning);
        else if (rec.value(1).toString()=="info") msgBox->setIcon(QMessageBox::Information);
        else if (rec.value(1).toString()=="error") msgBox->setIcon(QMessageBox::Critical);

        if(rec.value(1).toString()!="confirmation")
        {
                msgBox->setFont(font);
                msgBox->setWindowTitle(rec.value(1).toString());
                msgBox->setText(rec.value(2).toString());

                QSpacerItem* horizontalSpacer = new QSpacerItem(240, 290, QSizePolicy::Minimum, QSizePolicy::Minimum);
                QGridLayout* layout = (QGridLayout*)msgBox->layout();
                layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());

                msgBox->move(0,0);
                msgBox->exec();

                delete msgBox;

                ok = bdb.open();

                zapytanie.clear();
                zapytanie="update server_notifications set complete='1'";
                zapytanie.append(" where id='");
                zapytanie.append(QString::number(rec.value(0).toInt()));
                zapytanie.append("'");

                query.clear();
                query.prepare(zapytanie);
                ok = query.exec();
                query.clear();

                bdb.close();
            } else if (rec.value(1).toString()=="confirmation") {
                msgBox->setIcon(QMessageBox::Question);
                msgBox->setFont(font);
                msgBox->setWindowTitle(rec.value(1).toString());
                msgBox->setText(rec.value(2).toString());
                msgBox->setStandardButtons(QMessageBox::Yes | QMessageBox::No);

                QSpacerItem* horizontalSpacer = new QSpacerItem(240, 290, QSizePolicy::Minimum, QSizePolicy::Minimum);
                QGridLayout* layout = (QGridLayout*)msgBox->layout();
                layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());

                msgBox->move(0,0);
                int result = msgBox->exec();

                delete msgBox;

                ok = bdb.open();

                zapytanie.clear();
                if (result == QMessageBox::Yes) zapytanie="update server_notifications set complete='2'";
                else if (result == QMessageBox::No) zapytanie="update server_notifications set complete='3'";
                zapytanie.append(" where id='");
                zapytanie.append(QString::number(rec.value(0).toInt()));
                zapytanie.append("'");

                query.clear();
                query.prepare(zapytanie);
                ok = query.exec();
                query.clear();

                bdb.close();
            }
    }

    zapytanie.clear();
    rec.clear();
    queryModel.clear();
    odczytanoOstatnieKomunikaty=1;

    return ok;
}

bool MainWindow::wyswietlKomunikaty()
{
    if(odczytanoOstatnieKomunikaty==0)
    {

    } else
    {
        pobierzKomunikaty();
        odczytajNotificationInterval();
        timer.start(notificationInterval);
    }

    return 1;
}

bool MainWindow::odczytajNotificationInterval()
{
    bool ok;
    QTextStream out(stdout);
    QSqlRecord rec;
    QSqlQueryModel queryModel;

    ok = bdb.open();


    if (ok)
    {
        out << endl << "Otworzylem baze!" << endl ;
    } else {
        out << "Nie udalo sie otworzyc bazy!" << endl;
    }

    queryModel.clear();

    queryModel.setQuery("SELECT * FROM config WHERE name='qt-notification-interval'", bdb);

    rec = queryModel.record(0);
    notificationInterval = (rec.value(1).toInt())*1000;

#ifdef DEBUG
    out << "Notification interval: " << notificationInterval << " ms" << endl;
#endif

    rec.clear();
    queryModel.clear();
    bdb.close();

    return ok;
}

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And really I can't say nothing more. Like I said valgrind generates thousands of messages for QT applications. Problem is important because when program runs on ARM it takes minute after minute more memory resources.

thanks in advance
best regards
Tomasz

[wysota]

Here is an example app:

#include <QtGui>
 
 
int main(int argc, char **argv){
  QApplication app(argc, argv);
  QLineEdit *le = new QLineEdit;
  QString *str = new QString("xxx");
  le->setText(*str);
  le->show();
  return app.exec();
}

#include <QtGui>


int main(int argc, char **argv){
  QApplication app(argc, argv);
  QLineEdit *le = new QLineEdit;
  QString *str = new QString("xxx");
  le->setText(*str);
  le->show();
  return app.exec();
}

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And valgrind report for it (the parts that are relevant):

==12196== HEAP SUMMARY:
==12196== in use at exit: 195,287 bytes in 2,848 blocks
==12196== total heap usage: 72,096 allocs, 69,248 frees, 10,244,645 bytes allocated
==12196==
==12196== 4 bytes in 1 blocks are definitely lost in loss record 27 of 566
==12196== at 0x40244F0: operator new(unsigned int) (vg_replace_malloc.c:214)
==12196== by 0x8048811: main (main.cpp:7)
==12196==
==12196== 16,548 (20 direct, 16,528 indirect) bytes in 1 blocks are definitely lost in loss record 566 of 566
==12196== at 0x40244F0: operator new(unsigned int) (vg_replace_malloc.c:214)
==12196== by 0x80487ED: main (main.cpp:6)
==12196==
==12196== LEAK SUMMARY:
==12196== definitely lost: 1,401 bytes in 19 blocks
==12196== indirectly lost: 16,548 bytes in 113 blocks
==12196== possibly lost: 60,653 bytes in 611 blocks
==12196== still reachable: 116,685 bytes in 2,105 blocks
==12196== suppressed: 0 bytes in 0 blocks
==12196== Reachable blocks (those to which a pointer was found) are not shown.
==12196== To see them, rerun with: --leak-check=full --show-reachable=yes
==12196==
==12196== For counts of detected and suppressed errors, rerun with: -v
==12196== ERROR SUMMARY: 135 errors from 135 contexts (suppressed: 123 from 9)

You can see it immediately says where to look for problems. The rest of the reports in my case are either false positives or caused by Qt's dependencies (like KDE or fontconfig).

[Tomasz]

I've checked program with valgrind. It produced hundreds of messages.

It' starts with:

==27551== HEAP SUMMARY:
==27551==     in use at exit: 6,339,826 bytes in 16,037 blocks
==27551==   total heap usage: 239,607 allocs, 223,570 frees, 63,095,584 bytes allocated
==27551== 
==27551== 2 bytes in 1 blocks are possibly lost in loss record 5 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x50F2ED3: g_malloc (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x510B768: g_strdup (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x5121060: g_get_language_names (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x51153F9: g_thread_init_glib (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x50A360D: g_thread_init (in /usr/lib/libgthread-2.0.so.0.2400.1)
==27551==    by 0x4CFEAF0: QEventDispatcherGlibPrivate::QEventDispatcherGlibPrivate(_GMainContext*) (qeventdispatcher_glib.cpp:297)
==27551==    by 0x427F4CF: QGuiEventDispatcherGlibPrivate::QGuiEventDispatcherGlibPrivate() (qguieventdispatcher_glib.cpp:171)
==27551==    by 0x427F5C2: QGuiEventDispatcherGlib::QGuiEventDispatcherGlib(QObject*) (qguieventdispatcher_glib.cpp:186)
==27551==    by 0x4246454: QApplicationPrivate::createEventDispatcher() (qapplication_x11.cpp:606)
==27551==    by 0x4CD54B8: QCoreApplication::init() (qcoreapplication.cpp:555)
==27551==    by 0x4CD5726: QCoreApplication::QCoreApplication(QCoreApplicationPrivate&) (qcoreapplication.cpp:476)

==27551== HEAP SUMMARY:
==27551==     in use at exit: 6,339,826 bytes in 16,037 blocks
==27551==   total heap usage: 239,607 allocs, 223,570 frees, 63,095,584 bytes allocated
==27551== 
==27551== 2 bytes in 1 blocks are possibly lost in loss record 5 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x50F2ED3: g_malloc (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x510B768: g_strdup (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x5121060: g_get_language_names (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x51153F9: g_thread_init_glib (in /lib/libglib-2.0.so.0.2400.1)
==27551==    by 0x50A360D: g_thread_init (in /usr/lib/libgthread-2.0.so.0.2400.1)
==27551==    by 0x4CFEAF0: QEventDispatcherGlibPrivate::QEventDispatcherGlibPrivate(_GMainContext*) (qeventdispatcher_glib.cpp:297)
==27551==    by 0x427F4CF: QGuiEventDispatcherGlibPrivate::QGuiEventDispatcherGlibPrivate() (qguieventdispatcher_glib.cpp:171)
==27551==    by 0x427F5C2: QGuiEventDispatcherGlib::QGuiEventDispatcherGlib(QObject*) (qguieventdispatcher_glib.cpp:186)
==27551==    by 0x4246454: QApplicationPrivate::createEventDispatcher() (qapplication_x11.cpp:606)
==27551==    by 0x4CD54B8: QCoreApplication::init() (qcoreapplication.cpp:555)
==27551==    by 0x4CD5726: QCoreApplication::QCoreApplication(QCoreApplicationPrivate&) (qcoreapplication.cpp:476)

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There are a lot of messages like that above not connected directly with my code. Bu I've found a lot of like this:

[...]
 
==27551== 24 bytes in 1 blocks are possibly lost in loss record 1,088 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x7EFE9CA: sqlite3MemMalloc (sqlite3.c:12607)
==27551==    by 0x7EC92CF: mallocWithAlarm (sqlite3.c:15910)
==27551==    by 0x7EC93C7: sqlite3Malloc (sqlite3.c:15938)
==27551==    by 0x7F1DF40: unixOpen (sqlite3.c:25494)
==27551==    by 0x7EC8CF8: sqlite3OsOpen (sqlite3.c:12229)
==27551==    by 0x7EEB2F3: sqlite3BtreeFactory (sqlite3.c:34537)
==27551==    by 0x7EF4839: openDatabase (sqlite3.c:96157)
==27551==    by 0x7EC6774: QSQLiteDriver::open(QString const&, QString const&, QString const&, QString const&, int, QString const&) (qsql_sqlite.cpp:533)
==27551==    by 0x4039760: QSqlDatabase::open() (qsqldatabase.cpp:842)
==27551==    by 0x804C91F: MainWindow::pobierzKomunikaty() (in /home/tomek/projekt/start-build-desktop/start) //important???
==27551==    by 0x804E224: MainWindow::MainWindow(QWidget*) (in /home/tomek/projekt/start-build-desktop/start)
 
[...]
 
==27551== 32 bytes in 1 blocks are possibly lost in loss record 1,480 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x7EFE9CA: sqlite3MemMalloc (sqlite3.c:12607)
==27551==    by 0x7EC92CF: mallocWithAlarm (sqlite3.c:15910)
==27551==    by 0x7EC93C7: sqlite3Malloc (sqlite3.c:15938)
==27551==    by 0x7ED6F4B: sqlite3HashInsert (sqlite3.c:19830)
==27551==    by 0x7ED8CCC: sqlite3FindCollSeq (sqlite3.c:69693)
==27551==    by 0x7EF35DC: createCollation (sqlite3.c:95936)
==27551==    by 0x7EF4676: openDatabase (sqlite3.c:96137)
==27551==    by 0x7EC6774: QSQLiteDriver::open(QString const&, QString const&, QString const&, QString const&, int, QString const&) (qsql_sqlite.cpp:533)
==27551==    by 0x4039760: QSqlDatabase::open() (qsqldatabase.cpp:842)
==27551==    by 0x804C91F: MainWindow::pobierzKomunikaty() (in /home/tomek/projekt/start-build-desktop/start)
==27551==    by 0x804E224: MainWindow::MainWindow(QWidget*) (in /home/tomek/projekt/start-build-desktop/start)
==27551==
==27551== 32 bytes in 1 blocks are possibly lost in loss record 1,481 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x7EFE9CA: sqlite3MemMalloc (sqlite3.c:12607)
==27551==    by 0x7EC92CF: mallocWithAlarm (sqlite3.c:15910)
==27551==    by 0x7EC93C7: sqlite3Malloc (sqlite3.c:15938)
==27551==    by 0x7ED6F4B: sqlite3HashInsert (sqlite3.c:19830)
==27551==    by 0x7ED8CCC: sqlite3FindCollSeq (sqlite3.c:69693)
==27551==    by 0x7EF35DC: createCollation (sqlite3.c:95936)
==27551==    by 0x7EF46FD: openDatabase (sqlite3.c:96143)
==27551==    by 0x7EC6774: QSQLiteDriver::open(QString const&, QString const&, QString const&, QString const&, int, QString const&) (qsql_sqlite.cpp:533)
==27551==    by 0x4039760: QSqlDatabase::open() (qsqldatabase.cpp:842)
==27551==    by 0x804C91F: MainWindow::pobierzKomunikaty() (in /home/tomek/projekt/start-build-desktop/start)
==27551==    by 0x804E224: MainWindow::MainWindow(QWidget*) (in /home/tomek/projekt/start-build-desktop/start)
 
[...]

[...]

==27551== 24 bytes in 1 blocks are possibly lost in loss record 1,088 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x7EFE9CA: sqlite3MemMalloc (sqlite3.c:12607)
==27551==    by 0x7EC92CF: mallocWithAlarm (sqlite3.c:15910)
==27551==    by 0x7EC93C7: sqlite3Malloc (sqlite3.c:15938)
==27551==    by 0x7F1DF40: unixOpen (sqlite3.c:25494)
==27551==    by 0x7EC8CF8: sqlite3OsOpen (sqlite3.c:12229)
==27551==    by 0x7EEB2F3: sqlite3BtreeFactory (sqlite3.c:34537)
==27551==    by 0x7EF4839: openDatabase (sqlite3.c:96157)
==27551==    by 0x7EC6774: QSQLiteDriver::open(QString const&, QString const&, QString const&, QString const&, int, QString const&) (qsql_sqlite.cpp:533)
==27551==    by 0x4039760: QSqlDatabase::open() (qsqldatabase.cpp:842)
==27551==    by 0x804C91F: MainWindow::pobierzKomunikaty() (in /home/tomek/projekt/start-build-desktop/start) //important???
==27551==    by 0x804E224: MainWindow::MainWindow(QWidget*) (in /home/tomek/projekt/start-build-desktop/start)

[...]

==27551== 32 bytes in 1 blocks are possibly lost in loss record 1,480 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x7EFE9CA: sqlite3MemMalloc (sqlite3.c:12607)
==27551==    by 0x7EC92CF: mallocWithAlarm (sqlite3.c:15910)
==27551==    by 0x7EC93C7: sqlite3Malloc (sqlite3.c:15938)
==27551==    by 0x7ED6F4B: sqlite3HashInsert (sqlite3.c:19830)
==27551==    by 0x7ED8CCC: sqlite3FindCollSeq (sqlite3.c:69693)
==27551==    by 0x7EF35DC: createCollation (sqlite3.c:95936)
==27551==    by 0x7EF4676: openDatabase (sqlite3.c:96137)
==27551==    by 0x7EC6774: QSQLiteDriver::open(QString const&, QString const&, QString const&, QString const&, int, QString const&) (qsql_sqlite.cpp:533)
==27551==    by 0x4039760: QSqlDatabase::open() (qsqldatabase.cpp:842)
==27551==    by 0x804C91F: MainWindow::pobierzKomunikaty() (in /home/tomek/projekt/start-build-desktop/start)
==27551==    by 0x804E224: MainWindow::MainWindow(QWidget*) (in /home/tomek/projekt/start-build-desktop/start)
==27551==
==27551== 32 bytes in 1 blocks are possibly lost in loss record 1,481 of 3,561
==27551==    at 0x4023C4C: malloc (vg_replace_malloc.c:195)
==27551==    by 0x7EFE9CA: sqlite3MemMalloc (sqlite3.c:12607)
==27551==    by 0x7EC92CF: mallocWithAlarm (sqlite3.c:15910)
==27551==    by 0x7EC93C7: sqlite3Malloc (sqlite3.c:15938)
==27551==    by 0x7ED6F4B: sqlite3HashInsert (sqlite3.c:19830)
==27551==    by 0x7ED8CCC: sqlite3FindCollSeq (sqlite3.c:69693)
==27551==    by 0x7EF35DC: createCollation (sqlite3.c:95936)
==27551==    by 0x7EF46FD: openDatabase (sqlite3.c:96143)
==27551==    by 0x7EC6774: QSQLiteDriver::open(QString const&, QString const&, QString const&, QString const&, int, QString const&) (qsql_sqlite.cpp:533)
==27551==    by 0x4039760: QSqlDatabase::open() (qsqldatabase.cpp:842)
==27551==    by 0x804C91F: MainWindow::pobierzKomunikaty() (in /home/tomek/projekt/start-build-desktop/start)
==27551==    by 0x804E224: MainWindow::MainWindow(QWidget*) (in /home/tomek/projekt/start-build-desktop/start)

[...]

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And some like this:

==27551== 2,436 (256 direct, 2,180 indirect) bytes in 1 blocks are definitely lost in loss record 3,433 of 3,561
==27551==    at 0x4023D47: realloc (vg_replace_malloc.c:476)
==27551==    by 0x5270F56: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52719AC: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52720FB: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x527231F: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x5264A27: FcDefaultSubstitute (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x444849A: loadFc(QFontPrivate const*, int, QFontDef const&) (qfontdatabase_x11.cpp:1545)
==27551==    by 0x444B8E5: QFontDatabase::load(QFontPrivate const*, int) (qfontdatabase_x11.cpp:1939)
==27551==    by 0x4423C29: QFontPrivate::engineForScript(int) const (qfont.cpp:270)
==27551==    by 0x443BD26: QFontMetricsF::leading() const (qfontmetrics.cpp:1190)
==27551==    by 0x4359653: qt_format_text(QFont const&, QRectF const&, int, QTextOption const*, QString const&, QRectF*, int, int*, int, QPainter*) (qpainter.cpp:7738)
==27551==    by 0x435A695: QPainter::drawText(QRect const&, int, QString const&, QRect*) (qpainter.cpp:5807)
 
[...]
 
==27551== 4,872 (512 direct, 4,360 indirect) bytes in 2 blocks are definitely lost in loss record 3,483 of 3,561
==27551==    at 0x4023D47: realloc (vg_replace_malloc.c:476)
==27551==    by 0x5270F56: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52719AC: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52720FB: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x527231F: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x5264A27: FcDefaultSubstitute (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x444849A: loadFc(QFontPrivate const*, int, QFontDef const&) (qfontdatabase_x11.cpp:1545)
==27551==    by 0x444B8E5: QFontDatabase::load(QFontPrivate const*, int) (qfontdatabase_x11.cpp:1939)
==27551==    by 0x4423C29: QFontPrivate::engineForScript(int) const (qfont.cpp:270)
==27551==    by 0x445FC39: QScriptLine::setDefaultHeight(QTextEngine*) (qtextengine.cpp:2009)
==27551==    by 0x446F072: QTextLine::layout_helper(int) (qtextlayout.cpp:1756)
==27551==    by 0x4470F82: QTextLine::setLineWidth(double) (qtextlayout.cpp:1601)
 
[...]

==27551== 2,436 (256 direct, 2,180 indirect) bytes in 1 blocks are definitely lost in loss record 3,433 of 3,561
==27551==    at 0x4023D47: realloc (vg_replace_malloc.c:476)
==27551==    by 0x5270F56: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52719AC: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52720FB: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x527231F: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x5264A27: FcDefaultSubstitute (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x444849A: loadFc(QFontPrivate const*, int, QFontDef const&) (qfontdatabase_x11.cpp:1545)
==27551==    by 0x444B8E5: QFontDatabase::load(QFontPrivate const*, int) (qfontdatabase_x11.cpp:1939)
==27551==    by 0x4423C29: QFontPrivate::engineForScript(int) const (qfont.cpp:270)
==27551==    by 0x443BD26: QFontMetricsF::leading() const (qfontmetrics.cpp:1190)
==27551==    by 0x4359653: qt_format_text(QFont const&, QRectF const&, int, QTextOption const*, QString const&, QRectF*, int, int*, int, QPainter*) (qpainter.cpp:7738)
==27551==    by 0x435A695: QPainter::drawText(QRect const&, int, QString const&, QRect*) (qpainter.cpp:5807)

[...]

==27551== 4,872 (512 direct, 4,360 indirect) bytes in 2 blocks are definitely lost in loss record 3,483 of 3,561
==27551==    at 0x4023D47: realloc (vg_replace_malloc.c:476)
==27551==    by 0x5270F56: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52719AC: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x52720FB: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x527231F: ??? (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x5264A27: FcDefaultSubstitute (in /usr/lib/libfontconfig.so.1.4.4)
==27551==    by 0x444849A: loadFc(QFontPrivate const*, int, QFontDef const&) (qfontdatabase_x11.cpp:1545)
==27551==    by 0x444B8E5: QFontDatabase::load(QFontPrivate const*, int) (qfontdatabase_x11.cpp:1939)
==27551==    by 0x4423C29: QFontPrivate::engineForScript(int) const (qfont.cpp:270)
==27551==    by 0x445FC39: QScriptLine::setDefaultHeight(QTextEngine*) (qtextengine.cpp:2009)
==27551==    by 0x446F072: QTextLine::layout_helper(int) (qtextlayout.cpp:1756)
==27551==    by 0x4470F82: QTextLine::setLineWidth(double) (qtextlayout.cpp:1601)

[...]

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And the final summary looks like this:

==27551== LEAK SUMMARY:
==27551==    definitely lost: 2,344 bytes in 11 blocks
==27551==    indirectly lost: 11,360 bytes in 568 blocks
==27551==    possibly lost: 4,787,191 bytes in 8,606 blocks
==27551==    still reachable: 1,538,931 bytes in 6,852 blocks
==27551==    suppressed: 0 bytes in 0 blocks

==27551== LEAK SUMMARY:
==27551==    definitely lost: 2,344 bytes in 11 blocks
==27551==    indirectly lost: 11,360 bytes in 568 blocks
==27551==    possibly lost: 4,787,191 bytes in 8,606 blocks
==27551==    still reachable: 1,538,931 bytes in 6,852 blocks
==27551==    suppressed: 0 bytes in 0 blocks

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I haven't found any message connected directly with code. Functions mentioned in messages I've posted earlier.
Any idea?

thanks in advance
best regards
Tomasz