BUG: `onnx_api->RegisterExecutionProviderLibrary` causing double free error

[mdhvg]

Describe the issue

Onnxruntime C/C++ api causes a heap double free error when using
onnx_api->RegisterExecutionProviderLibrary(onnx_env, "openvino", ORT_TSTR("onnxruntime_providers_openvino.dll"));

To reproduce

• Compile onnxruntime using this command uv run onnxruntime\tools\ci_build\build.py --config Debug --build_shared_lib --parallel --compile_no_warning_as_error --skip_submodule_sync --skip_tests --use_dml --use_openvino --cmake_generator Ninja --build_dir "build" --cmake_extra_defines "onnxruntime_ENABLE_TRAINING=OFF" "onnxruntime_ENABLE_TRAINING_APIS=OFF" "onnxruntime_ENABLE_TRAINING_OPS=OFF" "onnxruntime_BUILD_BENCHMARKS=OFF" "OpenVINO_DIR=$pwd/deps/openvino/runtime/cmake"
• For openvino, I have used this OpenVINO release.
• After copying around the .dll files to the correct directories, this is the minimal reproducible code.

C API example

#include "stdio.h"
#include "stdint.h"
#include "onnxruntime_c_api.h"

#define Assert(x, ...)           \
    do                           \
    {                            \
        if (!x)                  \
        {                        \
            printf(__VA_ARGS__); \
            __debugbreak();      \
        }                        \
    } while (0)

int main()
{
    // Get api table
    const OrtApi *onnx_api = OrtGetApiBase()->GetApi(ORT_API_VERSION);
    Assert(onnx_api, "Failed to fetch ONNX Runtime API table");

    // setup ort env
    OrtEnv *onnx_env = NULL;
    OrtStatus *status = onnx_api->CreateEnv(ORT_LOGGING_LEVEL_INFO, "Session", &onnx_env);
    Assert(!status, "ORT API Error: %s", onnx_api->GetErrorMessage(status));

    status = onnx_api->RegisterExecutionProviderLibrary(onnx_env, "openvino", ORT_TSTR("onnxruntime_providers_openvino.dll"));
    Assert(!status, "ORT API Error: %s", onnx_api->GetErrorMessage(status));

    // cleanup
    onnx_api->UnregisterExecutionProviderLibrary(onnx_env, "openvino");

    if (onnx_env != NULL)
        onnx_api->ReleaseEnv(onnx_env);
}

C++ API example

#include <iostream>
#include "onnxruntime_cxx_api.h"

int main(int argc, char **argv)
{
    try
    {
        auto api = Ort::GetApi();
        auto env = Ort::Env(ORT_LOGGING_LEVEL_WARNING);
        env.RegisterExecutionProviderLibrary("openvino", L"onnxruntime_providers_openvino.dll");
    }
    catch (const std::runtime_error &err)
    {
        std::cerr << err.what() << std::endl;
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}

• This triggers the breakpoint in debug_alloc.cc:178

• And removing these lines fixes the error

C API

    status = onnx_api->RegisterExecutionProviderLibrary(onnx_env, "openvino", ORT_TSTR("onnxruntime_providers_openvino.dll"));
    Assert(!status, "ORT API Error: %s", onnx_api->GetErrorMessage(status));

    // cleanup
    onnx_api->UnregisterExecutionProviderLibrary(onnx_env, "openvino");

C++ API

        env.RegisterExecutionProviderLibrary("openvino", L"onnxruntime_providers_openvino.dll");

Urgency

This bug is not letting me incorporate OpenVINO for onnxruntime in my project. I'd say the issue is pretty urgent, even for onnxruntime itself because it can potentially break OpenVINO execution providers in applications that use onnxruntime for AI inference.

Platform

Windows

OS Version

10

ONNX Runtime Installation

Built from Source

ONNX Runtime Version or Commit ID

6c522b4

ONNX Runtime API

C and C++

Architecture

X64

Execution Provider

OpenVINO

Execution Provider Library Version

2026.2.1

[skottmckay]

What is the call stack when the debug breakpoint is hit?

[mdhvg]

Here's the call stack

	Name	Language
	ntdll.dll!00007ffbf018f412()	Unknown
	ntdll.dll!00007ffbf01981d2()	Unknown
	ntdll.dll!00007ffbf01984ba()	Unknown
	ntdll.dll!00007ffbf019e141()	Unknown
	ntdll.dll!00007ffbf01980e0()	Unknown
	ntdll.dll!00007ffbf00b5e1e()	Unknown
	ntdll.dll!00007ffbf00b5b74()	Unknown
	ntdll.dll!00007ffbf00b47b1()	Unknown
>	onnxruntime.dll!DebugHeapFree(void * p) Line 178	C++
	onnxruntime.dll!onnxruntime::ProviderHostImpl::HeapFree(void * p) Line 288	C++
	onnxruntime_providers_openvino.dll!operator delete(void * p, unsigned __int64 __formal) Line 82	C++
	onnxruntime_providers_openvino.dll!std::_Deallocate<16>(void * _Ptr, unsigned __int64 _Bytes) Line 289	C++
	onnxruntime_providers_openvino.dll!std::_Default_allocator_traits<std::allocatorstd::_Container_proxy>::deallocate(std::allocatorstd::_Container_proxy & _Al, std::_Container_proxy * const _Ptr, const unsigned __int64 _Count) Line 723	C++
	onnxruntime_providers_openvino.dll!std::_Deallocate_plain<std::allocatorstd::_Container_proxy>(std::allocatorstd::_Container_proxy & _Al, std::_Container_proxy * const _Ptr) Line 1139	C++
	onnxruntime_providers_openvino.dll!std::_Delete_plain_internal<std::allocatorstd::_Container_proxy>(std::allocatorstd::_Container_proxy & _Al, std::_Container_proxy * const _Ptr) Line 1151	C++
	onnxruntime_providers_openvino.dll!std::string::~basic_string<char,std::char_traits,std::allocator>() Line 1388	C++
	onnxruntime_providers_openvino.dll!std::string::`scalar deleting destructor'(unsigned int)	C++
	onnxruntime_providers_openvino.dll!std::destroy_atstd::string(std::string * const _Location) Line 337	C++
	onnxruntime_providers_openvino.dll!std::_Default_allocator_traits<std::allocatorstd::string>::destroystd::string(std::allocatorstd::string & __formal, std::string * const _Ptr) Line 739	C++
	onnxruntime_providers_openvino.dll!std::_Destroy_range<std::allocatorstd::string>(std::string * _First, std::string * const _Last, std::allocatorstd::string & _Al) Line 1103	C++
	onnxruntime_providers_openvino.dll!std::vector<std::string,std::allocatorstd::string>::_Tidy() Line 2093	C++
	onnxruntime_providers_openvino.dll!std::vector<std::string,std::allocatorstd::string>::~vector<std::string,std::allocatorstd::string>() Line 832	C++
	onnxruntime_providers_openvino.dll!onnxruntime::openvino_ep::OpenVINOEpPluginFactory::GetOvDevices'::2'::`dynamic atexit destructor for 'devices''()	C++
	ucrtbased.dll!00007ffb3e5c2b99()	Unknown
	ucrtbased.dll!00007ffb3e5c25c5()	Unknown
	ucrtbased.dll!00007ffb3e5c2717()	Unknown
	ucrtbased.dll!00007ffb3e5c2d44()	Unknown
	onnxruntime_providers_openvino.dll!__scrt_dllmain_uninitialize_c() Line 398	C++
	onnxruntime_providers_openvino.dll!dllmain_crt_process_detach(const bool is_terminating) Line 182	C++
	onnxruntime_providers_openvino.dll!dllmain_crt_dispatch(HINSTANCE__ * const instance, const unsigned long reason, void * const reserved) Line 220	C++
	onnxruntime_providers_openvino.dll!dllmain_dispatch(HINSTANCE__ * const instance, const unsigned long reason, void * const reserved) Line 293	C++
	onnxruntime_providers_openvino.dll!DllMainCRTStartup(HINSTANCE_ * const instance, const unsigned long reason, void * const reserved) Line 335	C++
	ntdll.dll!00007ffbf00a9a1d()	Unknown
	ntdll.dll!00007ffbf00fbadb()	Unknown
	ntdll.dll!00007ffbf00fb537()	Unknown
	ntdll.dll!00007ffbf009fd0a()	Unknown
	ntdll.dll!00007ffbf009fc84()	Unknown
	KernelBase.dll!00007ffbedd432de()	Unknown
	onnxruntime.dll!onnxruntime::WindowsEnv::UnloadDynamicLibrary(void * handle) Line 871	C++
	onnxruntime.dll!onnxruntime::ProviderLibrary::Unload() Line 2015	C++
	onnxruntime.dll!onnxruntime::EpLibraryProviderBridge::Unload() Line 55	C++
	onnxruntime.dll!onnxruntime::Environment::EpInfo::~EpInfo() Line 958	C++
	onnxruntime.dll!onnxruntime::Environment::EpInfo::`scalar deleting destructor'(unsigned int)	C++
	onnxruntime.dll!std::default_deleteonnxruntime::Environment::EpInfo::operator()(onnxruntime::Environment::EpInfo * _Ptr) Line 3309	C++
	onnxruntime.dll!std::unique_ptr<onnxruntime::Environment::EpInfo,std::default_deleteonnxruntime::Environment::EpInfo>::reset(onnxruntime::Environment::EpInfo * _Ptr) Line 3471	C++
	onnxruntime.dll!onnxruntime::Environment::UnregisterExecutionProviderLibrary(const std::string & registration_name) Line 723	C++
	onnxruntime.dll!OrtApis::UnregisterExecutionProviderLibrary(OrtEnv * env, const char * registration_name) Line 3746	C++
	bug.exe!main(...) Line 32	C
	bug.exe!invoke_main() Line 79	C++
	bug.exe!__scrt_common_main_seh() Line 288	C++
	bug.exe!__scrt_common_main() Line 331	C++
	bug.exe!mainCRTStartup(void * __formal) Line 17	C++
	kernel32.dll!00007ffbef4e7374()	Unknown
	ntdll.dll!00007ffbf00dcc91()	Unknown

[skottmckay]

I think you're creating a scenario where the OV EP is registered using both the legacy provider bridge and the new plugin interface. If you build with --use_openvino I wouldn't expect you need to do the plugin register/unregister.

[mdhvg]

So, you mean when I pass --use_openvino to build command, it's getting compiled into onnxruntime itself, just like DirectML? But, in that case, shouldn't OpenVINO show up as an available Execution Provider when I run something like this?

    uint64_t device_count = 0;
    const OrtEpDevice *const *ep_devices = NULL;
    status = g_ort->GetEpDevices(env, &ep_devices, &device_count);

    for (uint64_t i = 0; i < device_count; i++)
    {
        const OrtEpDevice *device = ep_devices[i];
        if (device != NULL)
        {
            printf("Device: %s - %s", g_ort->EpDevice_EpVendor(device), g_ort->EpDevice_EpName(device));
        }
    }

Output (With plugin registration removed):

 Device: Microsoft - CPUExecutionProvider
 Device: Microsoft - DmlExecutionProvider
 Device: Microsoft - DmlExecutionProvider

[skottmckay]

Yes. It's compiled into ORT, but the OV EP code supports both legacy and plugin usage which is a little confusing. Technically if you wanted to use OV as a plugin EP you'd need to do a build that way to create the OV EP library, and then a build without --use_openvino to create an ORT version that can use it as a plugin. The plugin EPs will be released separately to ORT so it makes more sense in that context as the user would get the ORT build from a different package to the OV EP build.

GetEpDevices reports plugin EPs only (although we fake a couple of internal EPs like DML to make them appear like a plugin EP).

If you're building OV into ORT you can use SessionOptionsAppendExecutionProvider to enable OV.

[mdhvg]

Ohh, That explains it. Alright then, seems like this issue is resolved now.
Thanks a lot for the help. Btw, could you point me to some example resources for ORT C/C++ API usage? I was using the onnxruntime-inference-examples/ort_tutorial/10_ep-device-selection as reference till now.