OCL sepFilter2D and Scharr freeze for several minutes

System Information

OpenCV version: 4.10.0 (appeared earlier?) Device: Nothing Phone 2 OS: Android 14 CPU: Qualcomm Snapdragon 8+ Gen1 iGPU: QUALCOMM Adreno(TM) (OpenCL 3.0 Adreno(TM) 730)

Detailed description

There are two test cases at which cv::sepFilter2D and cv::Scharr() misbehave, i.e. freeze for about 240 secs (Scharr) or 60 secs (sepFilter2D) and quit with wrong results.

In both cases they invoke OpenCL version and freeze at the same place after running col_filter kernel.

The test cases are:

OCL_Filter/Scharr3x3_cols16_rows2.Mat/26, where GetParam() = (8UC1, 0, 1x0, BORDER_REFLECT, 0.2, false, 1)

full ROI of size 16x30

kernel arguments:

-D RADIUSY=1 -D LSIZE0=16 -D LSIZE1=10 -D CN=1 -D srcT=float -D dstT=uchar
-D convertToFloatT=noconvert -D floatT=float -D convertToDstT=convert_uchar_sat_rte 
-D srcT1=float -D dstT1=uchar -D SHIFT_BITS=0
-D COEFF=DIG(0.6000000238f)DIG(2.000000000f)DIG(0.6000000238f)

OCL_ImageProc/SepFilter2D.Mat/10, where GetParam() = (CV_8U, Channels(1), BORDER_REFLECT, true, false)
full ROI of size 60x51

kernel arguments:

-D RADIUSY=3 -D LSIZE0=16 -D LSIZE1=10 -D CN=1 -D srcT=float -D dstT=uchar
-D convertToFloatT=noconvert -D floatT=float -D convertToDstT=convert_uchar_sat_rte
-D srcT1=float -D dstT1=uchar -D SHIFT_BITS=0
-D COEFF=DIG(0.008996695280f)DIG(-0.01206895430f)DIG(0.3683320880f)DIG(-0.1414978057f)DIG(-0.1748190373f)DIG(-0.1139794663f)DIG(-0.1803059429f)

The root cause is still unclear to me:

I've found only two such cases, no idea why these specific 2 cases among several hundreds
Changing local group size or turning off barriers does not change the behavior
All attempts to run this code with hardware sanitizer enabled result in an immediate segfault even before the first test is started

Steps to reproduce

Build OpenCV for ARM Android, upload binaries to device and run the tests.

CMake flags for build:

WITH_OPENCL : true
ANDROID_ABI : "arm64-v8a"
ANDROID_SDK : "~/Android/Sdk"
ANDROID_NDK : "~/Android/Sdk/ndk/26.1.10909125"
CMAKE_TOOLCHAIN_FILE : "~/Android/Sdk/ndk/26.1.10909125/build/cmake/android.toolchain.cmake"
BUILD_ANDROID_PROJECTS : false

Upload binary:

adb push ${OpenCV_build_directory}/bin/opencv_test_imgproc /data/local/tmp

Run:

adb shell '/data/local/tmp/opencv_test_imgproc --gtest_filter=*OCL_ImageProc/SepFilter2D.Mat/10'

adb shell '/data/local/tmp/opencv_test_imgproc --gtest_filter=*OCL_Filter/Scharr3x3_cols16_rows2.Mat/26'

Issue submission checklist

[X] I report the issue, it's not a question
[X] I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
[X] I updated to the latest OpenCV version and the issue is still there
[X] There is reproducer code and related data files (videos, images, onnx, etc)

Since the problem seems to be strictly related to a specific OpenCL implementation, I tried to write a better reproducer that contains as less extra code as possible. However, it behaves as a sort of Heisenbug, i.e. changing the source even a little sometimes makes the bug disappear. This means that stripping the reproducer code to its minimum may lead to reproducing some other bug.

So here's a one more reproducer for the separable filter case. It should replace the corresponding test in modules/imgproc/test/ocl/test_sepfilter2d.cpp file.

OCL_TEST_P(SepFilter2D, Mat)
{
    kernelX = cv::Mat{0.054970797, 0.23388229, -0.10257328, 0.13320626, -0.064946003, 0.26863641, 0.085793667, -0.0085192155, -0.047472052};
    kernelY = cv::Mat{0.0089966953, -0.012068954, 0.36833209, -0.14149781, -0.17481904, -0.11397947, -0.18030594};

    Size roiSize(60, 51);

    anchor.x = anchor.y = -1;
    delta = 66.015212;

    src = cv::Mat(roiSize, CV_8UC1, cv::Scalar(0));
    src.copyTo(usrc);

    usrc = cv::UMat(roiSize, CV_8UC1, cv::Scalar(0));
    udst = cv::UMat(roiSize, CV_8UC1, cv::Scalar(0));

    std::cout << "on:" << std::endl;
    cv::ocl::setUseOpenCL(true);
    cv::sepFilter2D(usrc, udst, -1, kernelX, kernelY, anchor, delta, borderType);

    std::cout << "finished" << std::endl;

    std::cout << "before copy..." << std::endl;
    src.copyTo(usrc);
    // this place is reached after some long time
    std::cout << "after copy..." << std::endl;
}

opencv / opencv