OpenCV cv::ocl::attachContext problem

Makefile

INC=-I/Users/rene/Code/OpenCL-Headers/opencl12
PKG=`pkg-config --cflags --libs opencv`
LD=`pkg-config --libs-only-L opencv | cut -c 3-`

.PHONY: default a.out.lldb
default: build
	LD_LIBRARY_PATH=$(LD) ./a.out

lldb: build a.out.lldb
	LD_LIBRARY_PATH=$(LD) lldb --source a.out.lldb

build:
	g++ $(PKG) $(INC) -glldb -g -framework OpenGL -framework OpenCL ocl-err.cpp

a.out.lldb:
	echo "env LD_LIBRARY_PATH=$(LD)\nfile a.out\nb UMatData::UMatData\nr\n" > a.out.lldb

ocl-err.cpp

#include <iostream>

#include <OpenGL/OpenGL.h>
#include <CL/cl.hpp>

#include <opencv2/core.hpp>
#include <opencv2/core/ocl.hpp>

#define CHECK(status, msg) if ((status) != CL_SUCCESS) \
{ \
  cout << (msg) << endl; \
  return -1; \
}

using namespace std;

class Foo
{
  public:
    Foo(const char* name) {
      cout << "new Foo(" << name << ") created!" << endl;
    };
    //~Foo() {
    //  cv::ocl::finish();
    //};

    int init();
    void process();

    static void clCallback(const char *errinfo, const void *private_info, size_t cb, void *user_data);

  private:
    std::vector<cl_platform_id> m_platform_ids;
    cl::Context m_clContext;
};

int Foo::init()
{
  cl_int res = CL_SUCCESS;

  std::vector<cl::Platform> platforms;
  cl::Platform::get(&platforms);

  cl::Platform defaultPlatform = cl::Platform::getDefault(&res);
  CHECK(res, "Failed to get default platform");

  cl_context_properties contextProps[] =
  {
    CL_CONTEXT_PLATFORM,
    (cl_context_properties)(defaultPlatform()),
    0
  };

  cout << "Creating a custom OpenCL context" << endl;

  m_clContext = cl::Context(CL_DEVICE_TYPE_GPU, contextProps, &Foo::clCallback, 0, &res);
  CHECK(res, "Failed to create OpenCL context");

  cout << "Created context (cl_context): " << m_clContext() << endl;

  cout << "Default OpenCV<>OpenCL Queue (cl_command_queue): " << cv::ocl::Queue::getDefault().ptr() << endl;

  std::vector<cl::Device> devs = m_clContext.getInfo<CL_CONTEXT_DEVICES>(&res);
  CHECK(res, "Failed to get devices from context");

  cout << "Attaching new context to OpenCV using first device: " << devs[0].getInfo<CL_DEVICE_NAME>() << endl;

  cv::ocl::attachContext(defaultPlatform.getInfo<CL_PLATFORM_NAME>(), defaultPlatform(), m_clContext(), devs[0]());

  cout << "Default OpenCV<>OpenCL Queue (cl_command_queue): " << cv::ocl::Queue::getDefault().ptr() << endl;
  return 0;
}

void Foo::process()
{
  cout << "Foo start processing" << endl;
  cout << "Create Mat with random data" << endl;

  cv::Mat data(100, 100, CV_8U);
  cv::randu(data, cv::Scalar(0), cv::Scalar(255));

  cout << "Uploading data to UMat" << endl;

  cv::UMat src;
  data.copyTo(src);

  cout << "Transposing UMat (t-api)" << endl;

  cv::transpose(src, src);
  cv::ocl::finish();

  cout << "Foo done processing" << endl;
}

void Foo::clCallback(const char *errinfo, const void *private_info, size_t cb, void *user_data)
{
  cout << endl << "OPENCL #" << endl << errinfo;
}

int main(int argc, char const *argv[])
{
  Foo *f0 = new Foo("f0");

  f0->init();
  f0->process();

  delete f0;

  Foo *f1 = new Foo("f1");

  f1->init();
  f1->process();

  delete f1;

  return 0;
}

ocl.diff

diff --git a/modules/core/src/ocl.cpp b/modules/core/src/ocl.cpp
index f25b9c0d7..9ea23b313 100644
--- a/modules/core/src/ocl.cpp
+++ b/modules/core/src/ocl.cpp
@@ -59,7 +59,7 @@
 
 #include "opencv2/core/bufferpool.hpp"
 #ifndef LOG_BUFFER_POOL
-# if 0
+# if 1
 #   define LOG_BUFFER_POOL printf
 # else
 #   define LOG_BUFFER_POOL(...)
@@ -3206,6 +3206,7 @@ public:
 #endif
         if (createFlags == 0)
         {
+            std::cout << "OpenCLAllocator: " << this << std::endl;
             allocatorFlags = ALLOCATOR_FLAGS_BUFFER_POOL_USED;
             handle = bufferPool.allocate(total);
         }

out.txt

g++ `pkg-config --cflags --libs opencv` -I/Users/rene/Code/OpenCL-Headers/opencl12 -glldb -g -framework OpenGL -framework OpenCL ocl-err.cpp
LD_LIBRARY_PATH=`pkg-config --libs-only-L opencv | cut -c 3-` ./a.out
new Foo(f0) created!
Creating a custom OpenCL context
Created context (cl_context): 0x7fd92af0cc80
Default OpenCV<>OpenCL Queue (cl_command_queue): 0x7fd92af0d810
Attaching new context to OpenCV using first device: Iris Pro
Default OpenCV<>OpenCL Queue (cl_command_queue): 0x7fd92af2b850
Foo start processing
Create Mat with random data
Uploading data to UMat
OpenCLAllocator: 0x7fd92af2b350
OpenCL allocate 12288 (0x3000) bytes: 0x7fd92af2b550
Transposing UMat (t-api)
Foo done processing
new Foo(f1) created!
Creating a custom OpenCL context
Created context (cl_context): 0x7fd92af2cc10
Default OpenCV<>OpenCL Queue (cl_command_queue): 0x7fd92af2b850
Attaching new context to OpenCV using first device: Iris Pro
Default OpenCV<>OpenCL Queue (cl_command_queue): 0x7fd92af2b120
Foo start processing
Create Mat with random data
Uploading data to UMat
OpenCLAllocator: 0x7fd92af2b350
Reuse reserved buffer: 0x7fd92af2b550

OPENCL #
OpenCV Error: Assertion failed (clEnqueueWriteBuffer(q, (cl_mem)u->handle, CL_TRUE, dstrawofs, total, alignedPtr.getAlignedPtr(), 0, 0, 0) >= 0) in upload, file /Users/rene/Code/opencv/modules/core/src/ocl.cpp, line 3984
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /Users/rene/Code/opencv/modules/core/src/ocl.cpp:3984: error: (-215) clEnqueueWriteBuffer(q, (cl_mem)u->handle, CL_TRUE, dstrawofs, total, alignedPtr.getAlignedPtr(), 0, 0, 0) >= 0 in function upload

[CL_INVALID_CONTEXT] : OpenCL Error : clEnqueueWriteBuffer failed: cl_mem object belongs to a different context 0x7fd92af0cc80 than the queue's context 0x7fd92af2cc10.make: *** [default] Abort trap: 6

PKG_CONFIG_PATH must be set accordingly before the Makefile can be used.