What is the issue?

We've got CI failing in some tests in windows-race. In each of these cases, the test program cannot even start.

I did find this Go issue discussing the problem, but it looked like nobody really understood the reason behind the VirtualAlloc failure.

The base address that TSan wants to use for allocating shadow memory is invalid because it is higher than the maximum virtual address permitted by the kernel for user-mode VM allocation requests.

If I'm reading the existing analysis so far, the concern is around the computation of the base address here.

Steps to reproduce

No response

Are there any recent changes that introduced the issue?

No response

OS

Windows

OS version

No response

Tailscale version

No response

Bug report

No response