Basic install hangs umount at startup

[evanphx]

Description

Installed runsc and configured it in containerd using the quickstart. Then attempting to run a trivial container via ctr results in a hang at startup. Here is the ps output:

  98391 pts/4    S+     0:00 sudo ctr -n lab run --runtime /usr/bin/containerd-shim-runsc-v1 docker.io/library/alpine:latest c1
  98392 pts/2    Ss     0:00 sudo ctr -n lab run --runtime /usr/bin/containerd-shim-runsc-v1 docker.io/library/alpine:latest c1
  98393 pts/2    Sl+    0:00 ctr -n lab run --runtime /usr/bin/containerd-shim-runsc-v1 docker.io/library/alpine:latest c1
  98414 ?        Sl     0:00 /usr/bin/containerd-shim-runsc-v1 -namespace lab -address /run/containerd/containerd.sock -publish-binary /usr/bin/containerd
  98427 ?        Ssl    0:00 runsc-gofer --root=/run/containerd/runsc/lab --log=/run/containerd/io.containerd.runtime.v2.task/lab/c1/log.json --log-format=json --log-fd=3 gofer --bundle=/run/containerd/io.containerd.runtime.v2.task/lab/c1 --io-fds=6 --mounts-fd=5 --overlay-mediums=2 --spec-fd=4 --setup-root=false --sync-nvproxy-fd=-1 --sync-userns-fd=-1 --proc-mount-sync-fd=14 --apply-caps=false
  98431 ?        Ssl    0:00 runsc-sandbox --root=/run/containerd/runsc/lab --log=/run/containerd/io.containerd.runtime.v2.task/lab/c1/log.json --log-format=json --log-fd=3 boot --apply-caps=false --bundle=/run/containerd/io.containerd.runtime.v2.task/lab/c1 --controller-fd=8 --cpu-num=8 --io-fds=4 --mounts-fd=6 --overlay-filestore-fds=5 --overlay-mediums=2 --setup-root=false --spec-fd=9 --start-sync-fd=7 --stdio-fds=10,11,12 --total-host-memory=8008323072 --total-memory=8008323072 --proc-mount-sync-fd=20 --product-name=DMAF5 c1
  98444 ?        Sl     0:00 /proc/self/exe umount --sync-fd=3 /proc
  98460 ?        Ss     0:00 [exe]
  98461 ?        S      0:00 [exe]

Steps to reproduce

Perform basic install, run:

ctr -n lab pull docker.io/library/alpine:latest
ctr -n lab run --runtime /usr/bin/containerd-shim-runsc-v1 docker.io/library/alpine:latest c1

runsc version

runsc version release-20230807.0

docker version (if using docker)

No response

uname

Linux mu 5.15.0-78-generic #85-Ubuntu SMP Fri Jul 7 15:25:09 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

kubectl (if using Kubernetes)

No response

repo state (if built from source)

No response

runsc debug logs (if available)

I'm unable to figure out how to produce the runsc logs when using running directly via containerd.

[evanphx]

It appears that docker doesn't use the runsc shim, but rather uses the normal runc shim and provides a secondary binary name. When I do that using the containerd go api directly by using, as an argument to NewContainer:

containerd.WithRuntime("io.containerd.runc.v2", &options.Options{
   BinaryName: "runsc",
}

The runsc does start up correctly and runs.

[evanphx]

Oh, using docker works fine too, that's how I discovered that it didn't use the runsc-shim.

[evanphx]

ah ah, this is the same as #4544.