onnxruntime

a2cd643d - Fix loader-refcount leak in ProviderLibrary::Load on GetProvider miss (#28396)

Fix loader-refcount leak in ProviderLibrary::Load on GetProvider miss (#28396) ### Description Fixes a loader-refcount leak in `ProviderLibrary::Load()` that affects any caller of `OrtApi::RegisterExecutionProviderLibrary` whose target DLL does not export `GetProvider` (i.e. plugin EPs that are not legacy provider-bridge libraries). In `onnxruntime/core/session/utils.cc`, [`LoadPluginOrProviderBridge`](https://github.com/microsoft/onnxruntime/blob/main/onnxruntime/core/session/utils.cc#L852) probes whether the EP DLL is a "provider bridge" by constructing a temporary `ProviderLibrary` and calling `Load()`: ```cpp auto provider_library = std::make_unique<ProviderLibrary>(...); bool is_provider_bridge = provider_library->Load() == Status::OK(); // (+1) loader ref ... auto ep_library_plugin = std::make_unique<EpLibraryPlugin>(...); ORT_RETURN_IF_ERROR(ep_library_plugin->Load()); // (+1) loader ref ``` `ProviderLibrary::Load()` calls `LoadDynamicLibrary` (handle_=1), then `GetSymbolFromLibrary("GetProvider", ...)`. For a plugin EP DLL that does not export `GetProvider`, the lookup fails and `ORT_RETURN_IF_ERROR` returns the `Status` early — without calling `Unload()`. The surrounding `try/catch` only catches `std::exception`, so the early return is not covered. `~ProviderLibrary()` is empty (intentionally, to avoid static-destruction-order issues with the global `s_library_*` instances), so the temporary's `handle_` is silently leaked. `EpLibraryPlugin::Load()` then maps the same DLL again (refcount → 2). Later, `UnregisterExecutionProviderLibrary` releases only the reference owned by `EpLibraryPlugin`, leaving the EP DLL mapped (refcount = 1) after the caller explicitly unregistered it. Static / thread-local destructors that need the EP DLL outlive `Unregister` and run at process exit in an inconsistent order — on Windows this often manifests as a `STATUS_STACK_BUFFER_OVERRUN` (`0xC0000409`) fast-fail during teardown. ### Fix In `ProviderLibrary::Load()`, when `GetSymbolFromLibrary("GetProvider", ...)` fails, call `Unload()` before returning the error: ```cpp auto get_provider_status = Env::Default().GetSymbolFromLibrary(handle_, "GetProvider", (void**)&PGetProvider); if (!get_provider_status.IsOK()) { Unload(); return get_provider_status; } provider_ = PGetProvider(); ``` This keeps the existing `~ProviderLibrary()` contract (callers are still expected to call `Unload()` themselves on success paths), but plugs the early-return-after-`LoadDynamicLibrary` leak. ### Verification Standalone repro that does only `LoadLibraryExW("onnxruntime.dll")` → `RegisterExecutionProviderLibrary("VitisAIExecutionProvider", L"onnxruntime_vitisai_ep.dll")` → `UnregisterExecutionProviderLibrary` → `ReleaseEnv`, then drains `FreeLibrary` on the EP DLL counting iterations: https://github.com/BoarQing/ep_double_load_repro | build | output | |---|---| | `main` (unpatched) | `ep dll leaked refcount after Unregister+ReleaseEnv = 1` | | `main` + this PR | `ep dll leaked refcount after Unregister+ReleaseEnv = 0` | Tracking issue: #28395 Co-authored-by: BoarQing <boarqing@users.noreply.github.com>