Memory leak when using postMessage from new thread

[ArnaudVERSINI]

Windows Build Number

Win32NT 10.0.26100.0 Microsoft Windows NT 10.0.26100.0

Processor Architecture

AMD64

Memory

64GB

Storage Type, free / capacity

1TB

Relevant apps installed

None, just Windows

Traces collected via Feedback Hub

None

Isssue description

memory leak in PostMessage from user32.dll

Steps to reproduce

Everytime I use PostMessage in a new thread it leaks 8 bytes with a 32bits application and16 bytes with a 64bits application. This should not be the case.

Build and run the application from https://github.com/ArnaudVERSINI/user32_memory_leak/ using cargo run --release and wait, memory will increase.

Expected Behavior

No memory leaks like on Windows 10

Actual Behavior

Memory leaks only on Windows 11

[ArnaudVERSINI]

Please Microsoft this bug is annoying on Windows 11 and is a regression from Windows 10. You have all necessary code to reproduce the issue !

Thanks in advance

[RegisPerdreau]

Seen on

Édition Windows 11 Professionnel
Version 24H2

Build du système d’exploitation 26100.4652
Expérience Pack d’expérience de fonctionnalités Windows 1000.26100.128.0

[yannicklaurent31]

Same problem on Windows 11 Professionnel 24H2 Build 26100.4770.

This regression is really critical and needs to be fixed urgently.