why the result of filter2D function is correct on cpu and wrong on gpu??

edit

The processing on the GPU give me wrong result and noise(not randomly). This is my code :

Mat ker(3,3,CV_8S);
// gain=0
ker.at<char>(0,0)=-(1+gain),ker.at<char>(0,1)=-(1+gain),ker.at<char>(0,2)=-(1+gain);
ker.at<char>(1,0)=-(1+gain),ker.at<char>(1,1)=(1+gain)*8,ker.at<char>(1,2)=-(1+gain);
ker.at<char>(2,0)=-(1+gain),ker.at<char>(2,1)=-(1+gain),ker.at<char>(2,2)=-(1+gain);
Mat test(taille,taille,CV_8UC1,125);
for(int x=0;x<taille;x++)
{
    for(int y=0;y<taille;y++)
    {
     //   test.at<uchar>(y,x)=((x%2)^(y%2))*255; //corect
            test.at<uchar>(y,x)=x+y;
    }
}
Mat res;
Mat temp;
test.copyTo((temp,test));
GpuMat resgpu(test);

test.copyTo(res,test);
filter2D(res,res,res.depth(),ker);
filter2D(resgpu,resgpu,resgpu.depth(),ker);
vector<int> compression_params;
compression_params.push_back(CV_IMWRITE_JPEG_QUALITY );
compression_params.push_back(100);

imwrite("aze.jpg",test,compression_params);
imwrite("aze_filtre.jpg",res,compression_params);
imwrite("aze_filtre_gpu.jpg",Mat(resgpu),compression_params);

correct:cpu:

:

wrong:gpu: