fromCvMat in camcalib produce segFault

[gonzalezJohnas]

This bug has been found and solve with the help of Andrea Ruzzenenti (@aerydna)

Describe the bug
When running camCalib from icub-main and more specifically in the PinholeCalibTool::apply function produce a null image after fromCvMat<PixelRgb> resulting in a segfault.

We found that the issue is in reality in libYARP_sig/src/Image.cpp for the function Image& Image::operator=(Image&& other).

To Reproduce
Connect camCalib module to yarpdev (grabberDual)

Expected behavior
The image returned from fromCvMat<PixelRgb> after applying the calibration with remap is not valid so accessing is pixel produce a segfault.

Configuration :

• OS: Ubuntu 18.04
• yarp version: 3.0 branch devel
• compiler: gcc, g++ version 7.3.0

Temporary fix
The actual bug happen in the libYARP_sig/src/Image.cpp :

Image& Image::operator=(Image&& other) {
    Image moved(std::move(other));
    std::swap(moved.implementation, implementation);
    synchronize();
    return *this;
}

When performing the swap if moved.implementation is not set to nullptr, the Image destructor is called on moved destroying also the implementation of the current object (this).

A way to fix it is to explicitly set moved.implementation to nullptr before the synchronize or before the swap.

For more details you can contact me or Andrea Ruzzenenti (@aerydna)

[drdanz]

Thanks for reporting this.
It's fixed in devel now.

[Nicogene]

The move operators were correct, the commit that add nullptr has been reverted since it introduced memory leak.

The bug was in camCalib, it has been fixed by robotology/icub-main#572