Runtime failure with Steam in chroot: bwrap: Can't mkdir parents for /run/host/usr

[dsalt]

Proton 5.13 fails to start up due to the new runtime (Steam Linux Runtime - Solder) expecting either /run/host to exist or to have write access to /run. With the runtime eliminated (launch command set to run Proton directly for the game under test) all is well.

Is it expecting systemd, working containers, multiple instances of /run or something?

[dsalt]

$ ls -ldZ /run /run/host
ls: cannot access '/run/host': No such file or directory
drwxr-xr-x 27 root root 1180 Oct 17 16:31 /run/

Looks like it's a collision between bwrap and the environment. in which I'm running Steam – basically, chroot. Current setup has, within that, recursive bind mounts on /proc, /sys and /run, normal bind mounts on /dev and /dev/pts, and a tmpfs on /dev/shm.

[smcv]

Running Steam in a chroot is not really supported and has not been tested. I've seen problems with bwrap in a chroot before: it uses pivot_root(2) to set up the root of the container, and I think being in a chroot might be breaking its assumptions there.

@kisak-valve, please could you retitle this issue to something like Runtime failure with Steam in chroot: bwrap: Can't mkdir parents for /run/host/usr to flag the use of a chroot as an important factor?

The /run inside the container is meant to be a tmpfs that is unrelated to the /run outside the container, but I think your use of a chroot might be confusing the setup code.

[smcv]

The information requested in https://github.com/ValveSoftware/steam-runtime/blob/master/doc/reporting-steamlinuxruntime-bugs.md would probably be useful here.