X connection to :100 broken (explicit kill or server shutdown).

[Kreijstal]

hmm somehow can´t start this docker at all anymore.

[pipcet]

Same here.

I tried using qemu to run the "nocloud" image from https://cloud.debian.org/images/cloud/sid/daily/20250524-2122/ , and started the msys2-docker-experimental image from within the qemu session, and that appeared to work.

That makes it seem like it's a kernel or kernel configuration issue, but I haven't been able to investigate further.

[Kreijstal]

how to debug this?

[pipcet]

This may or may not be helpful: I worked out that it wasn't the kernel difference that made the debian-in-qemu setup work, it was the lack of a CPU feature in the emulated CPU, and I finally figured out which one: PKU.

If you run Linux, could you try appending nopku to the kernel command line and seeing whether that fixes the problem for you?

However, the PKU feature is very useful and we don't want to disable it permanently! This is, at best, a temporary solution and a hint for the wine/msys2 folks to know where to start looking...

[pipcet]

Found it, see the msys2-runtime issue here:

msys2/msys2-runtime#295 .

This requires fixing in the msys2 runtime, and possibly the upstream Cygwin code. I'll have a look and report it there, too, if necessary.