ORT 1.25.2 Cherry Picks, Round 2#28426
Merged
Merged
Conversation
…#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>
adrianlizarraga
approved these changes
May 8, 2026
skottmckay
approved these changes
May 10, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This cherry-picks the following commits for the release:
#28396 Fix loader-refcount leak in ProviderLibrary::Load on GetProvider miss