Windows 2025 hang on loading an invalid library

[mwestphal]

Description

Since the new Windows 2025 started deploying, we are seeing an regression in our CI.
We have a code that can load DLLs as plugin, we test this code for error code path, so we have two test that uses invalid DLL files that are loaded using LoadLibraryExW.

These two tests now hangs systematically on the LoadLibraryExW call and ends up in timeout.

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 20.04
• Ubuntu 22.04
• Ubuntu 24.04
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Image version and build link

Started failing with 20250330.1.0
Example: https://github.com/f3d-app/f3d/actions/runs/14228619281/job/39874643434

Is it regression?

yes,
It does not fails with 20250324.3.0
Example: https://github.com/f3d-app/f3d/actions/runs/14180563686/job/39785122474

Expected behavior

No hangs when calling LoadLibraryExW with an invalid dlls and error reporting with something like "is not a valid Win32 application"

Actual behavior

Hangs when calling LoadLibraryExW with an invalid dll.

Repro steps

Run a CI with windows-latest that calls LoadLibraryExW with an invalid DLL.

• fork f3d-app/f3d
• create a branch
• make a non-impactful change, push to your fork
• create a PR against f3d-app/f3d
• wait for windows CI to run

[kishorekumar-anchala]

hi @mwestphal

Thank you for bringing this issue to our attention. We will look into this issue and will update you after investigating.

[subir0071]

Hi @mwestphal - Unfortunately, It is prohibitively difficult for us to run through tons of log messages in individual user repository, where we do not even have insight into the problem that those repositories are solving.

Please help with a small workflow that specifically directs us to the error message or helps us reproduce the issue at our end.
Thanks.

[mwestphal]

Thanks for the feedback @subir0071 . I'll create a small repo. I may take a while though