QPainter + QImage::Format_Grayscale8 bug + drawText

Start from Qt 5.9.1, when i draw text, on QImage, in some resolutions (if one side of image >= 2051px), when it use Grayscale8 color space, and this text, still outside image region (intersect of one image side), i get crash:

*** stack smashing detected ***: <unknown> terminated

The program has unexpectedly finished.

#include <QGuiApplication>
#include <QCoreApplication>
#include <QImage>
#include <QPainter>

int main(int argc, char *argv[])
{
    QGuiApplication a(argc, argv);
    QImage img(2051, 100, QImage::Format_Grayscale8);
    QPainter p;    
    p.begin(&img);
    p.eraseRect(QRect(QPoint(0,0),img.size()));
    QFont f=p.font();
    f.setPointSize(10);
    p.setFont(f);

//create rect, interset of one side image
    QRect textRect(img.width()-50,30,100,50);
    QString text("hello world!");

    p.setBrush(QBrush(QColor(0,0,0,200)));
    p.setPen(Qt::NoPen);
    p.drawRect(textRect);
    p.setPen(QColor(255,255,255,255));
    //at rhis point, i have crash:
    //*** stack smashing detected ***: <unknown> terminated
    //The program has unexpectedly finished.
    p.drawText(textRect, 0, text);

    p.end();
    img.save("/home/nick1710/testimage.png");
}

I upload sample program, to repeat bug. In Qt 5.6 all work fine.