System Information

OpenCV version: 4.8.0
Operating System / Platform: openSUSE Tumbleweed (VERSION_ID="20231008")
Compiler & compiler version: gcc (SUSE Linux) 13.1.1 20230710 [revision f9781fcf733ca3afe5b5811afd8ecbb18d9d3a11]

Detailed description

Inside the function oclCvtColorBGR2HSV (color_hsv.dispatch.cpp) variables are defined as static so that they are initialized only once. That can lead to race conditions and OpenCL-context conflicts. Instead of static these variables should be declared static thead_local;

Steps to reproduce

#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <thread>
int main() {
	std::thread t([](){
		cv::UMat src(cv::Size(1280, 720), CV_8UC3);
		cv::UMat dst;
		while(true) {
			cvtColor(src, dst, cv::COLOR_BGR2HSV);
		}
	});

	cv::UMat src(cv::Size(1280, 720), CV_8UC3);
	cv::UMat dst;

	while(true) {
		cvtColor(src, dst, cv::COLOR_BGR2HSV);
	}
}

Issue submission checklist

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