ocl::OpenCLExecutionContext::create(Context&, Device&) fails when device is created independently

[hedgepigdaniel]

System information (version)

• OpenCV => 4.5.3-dev (aaca498)

Detailed description

https://docs.opencv.org/4.5.2/d7/d83/classcv_1_1ocl_1_1OpenCLExecutionContext.html#a2890cfb4b198f7621590a2c0de4465fc

Due to the check in _init_device here, ocl::OpenCLExecutionContext::create(Context&, Device&) requires that the device wrapper passed in (i.e. the Device, not just the cl_device_id) is one of the Devices in the Context.

This is not the case if the user does the following:

cl_context context = get_opencl_context_from_outside_opencv();
cl_device_id device = get_opencl_device_from_outside_opencv(context);

ocl::OpenCLExecutionContext opencv_context = ocl::OpenCLExecutionContext::create(
    ocl::Context::fromHandle(context),
    ocl::Device::fromHandle(device));

Despite the underlying OpenCL device ids being the same:

(gdb) n
866	        int ndevices = (int)context_.ndevices();
(gdb) n
867	        CV_Assert(ndevices > 0);
(gdb) print ndevices
$1 = 1
(gdb) n
868	        bool found = false;
(gdb) n
869	        for (int i = 0; i < ndevices; i++)
(gdb) n
871	            ocl::Device d = context_.device(i);
(gdb) n
872	            if (d.getImpl() == device.getImpl())
(gdb) print d
$2 = {p = 0x7fff80003d70}
(gdb) print device
$3 = (const cv::ocl::Device &) @0x7fff9affcce8: {p = 0x7fff80000b60}
(gdb) d.ptr()
Undefined command: "d.ptr".  Try "help".
(gdb) print d.ptr()
$4 = (void *) 0x555555727780
(gdb) print device.ptr()
$5 = (void *) 0x555555727780
(gdb) print device.getImpl()
$6 = (cv::ocl::Device::Impl *) 0x7fff80000b60
(gdb) print d.getImpl()
$7 = (cv::ocl::Device::Impl *) 0x7fff80003d70

The result is an exception:

#0  0x00007ffff698bd22 in raise () from /usr/lib/libc.so.6
#1  0x00007ffff6975862 in abort () from /usr/lib/libc.so.6
#2  0x00007ffff6bcf802 in __gnu_cxx::__verbose_terminate_handler () at /build/gcc/src/gcc/libstdc++-v3/libsupc++/vterminate.cc:95
#3  0x00007ffff6bdbc8a in __cxxabiv1::__terminate (handler=<optimized out>) at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:48
#4  0x00007ffff6bdbcf7 in std::terminate () at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:58
#5  0x00007ffff6bdbf8e in __cxxabiv1::__cxa_throw (obj=<optimized out>, tinfo=0x7ffff7f42878 <typeinfo for cv::Exception>, dest=0x7ffff714a724 <cv::Exception::~Exception()>) at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_throw.cc:95
#6  0x00007ffff714cc17 in cv::error (exc=...) at /home/daniel/code/oss/opencv/modules/core/src/system.cpp:1166
#7  0x00007ffff714cce4 in cv::error (_code=-215, _err="found && \"OpenCL device can't work with passed OpenCL context\"", _func=0x7ffff7b78c41 "_init_device", 
    _file=0x7ffff7b78440 "/home/daniel/code/oss/opencv/modules/core/src/ocl.cpp", _line=879) at /home/daniel/code/oss/opencv/modules/core/src/system.cpp:1178
#8  0x00007ffff70825e9 in cv::ocl::OpenCLExecutionContext::Impl::_init_device (this=0x7fff80002220, device=...) at /home/daniel/code/oss/opencv/modules/core/src/ocl.cpp:879
#9  0x00007ffff7082c2e in cv::ocl::OpenCLExecutionContext::Impl::Impl (this=0x7fff80002220, context=..., device=...) at /home/daniel/code/oss/opencv/modules/core/src/ocl.cpp:913
#10 0x00007ffff70c170d in __gnu_cxx::new_allocator<cv::ocl::OpenCLExecutionContext::Impl>::construct<cv::ocl::OpenCLExecutionContext::Impl, cv::ocl::Context const&, cv::ocl::Device const&> (this=0x7fff96ffcadf, __p=0x7fff80002220)
    at /usr/include/c++/11.1.0/ext/new_allocator.h:156
#11 0x00007ffff70c06e5 in std::allocator_traits<std::allocator<cv::ocl::OpenCLExecutionContext::Impl> >::construct<cv::ocl::OpenCLExecutionContext::Impl, cv::ocl::Context const&, cv::ocl::Device const&> (__a=..., __p=0x7fff80002220)
    at /usr/include/c++/11.1.0/bits/alloc_traits.h:512
#12 0x00007ffff70be81e in std::_Sp_counted_ptr_inplace<cv::ocl::OpenCLExecutionContext::Impl, std::allocator<cv::ocl::OpenCLExecutionContext::Impl>, (__gnu_cxx::_Lock_policy)2>::_Sp_counted_ptr_inplace<cv::ocl::Context const&, cv::ocl::Device const&> (this=0x7fff80002210, __a=...) at /usr/include/c++/11.1.0/bits/shared_ptr_base.h:519
#13 0x00007ffff70bc63d in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::__shared_count<cv::ocl::OpenCLExecutionContext::Impl, std::allocator<cv::ocl::OpenCLExecutionContext::Impl>, cv::ocl::Context const&, cv::ocl::Device const&> (
    this=0x7fff96ffcc78, __p=@0x7fff96ffcc70: 0x0, __a=...) at /usr/include/c++/11.1.0/bits/shared_ptr_base.h:650
#14 0x00007ffff70b980d in std::__shared_ptr<cv::ocl::OpenCLExecutionContext::Impl, (__gnu_cxx::_Lock_policy)2>::__shared_ptr<std::allocator<cv::ocl::OpenCLExecutionContext::Impl>, cv::ocl::Context const&, cv::ocl::Device const&> (
    this=0x7fff96ffcc70, __tag=...) at /usr/include/c++/11.1.0/bits/shared_ptr_base.h:1337
#15 0x00007ffff70b4d1c in std::shared_ptr<cv::ocl::OpenCLExecutionContext::Impl>::shared_ptr<std::allocator<cv::ocl::OpenCLExecutionContext::Impl>, cv::ocl::Context const&, cv::ocl::Device const&> (this=0x7fff96ffcc70, __tag=...)
    at /usr/include/c++/11.1.0/bits/shared_ptr.h:409
#16 0x00007ffff70af2d5 in std::allocate_shared<cv::ocl::OpenCLExecutionContext::Impl, std::allocator<cv::ocl::OpenCLExecutionContext::Impl>, cv::ocl::Context const&, cv::ocl::Device const&> (__a=...)
    at /usr/include/c++/11.1.0/bits/shared_ptr.h:861
#17 0x00007ffff70a7a4b in std::make_shared<cv::ocl::OpenCLExecutionContext::Impl, cv::ocl::Context const&, cv::ocl::Device const&> () at /usr/include/c++/11.1.0/bits/shared_ptr.h:877
#18 0x00007ffff7084dbe in cv::ocl::OpenCLExecutionContext::create (context=..., device=...) at /home/daniel/code/oss/opencv/modules/core/src/ocl.cpp:1136

Steps to reproduce

You can reproduce with a small modification to the reproduction here: #20518

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 solution
• I updated to latest OpenCV version and the issue is still there
• There is reproducer code and related data files: videos, images, onnx, etc

[hedgepigdaniel]

replacing

if (d.getImpl() == device.getImpl())

with

if (d.ptr() == device.ptr())

fixes the problem, but results in a net decrease in the reference count of the passed device - because a reference is not kept to it.

[alalek]

There is a prerequisite that ocl::Context should be created using the passed ocl::Device.

ocl::Device may have the same cl_device handler, but extra OpenCV-specific configuration may be different - e.g. used max work group size (for cases like #13108).