Preparation:
1. Install Fedora 31 Silverblue.
2. Ensure that you have a sub?id range set up appropriately.


$ podman run --rm -it fedora:latest
Trying to pull docker.io/library/fedora:latest...
Getting image source signatures
Copying blob 5a915a173fbc done
Copying config e9ed59d2ba done
Writing manifest to image destination
Storing signatures

After this point podman hangs.

$ strace -f -p `pidof /usr/bin/crun`
strace: Process 9511 attached
select(4, [3], NULL, NULL, {tv_sec=0, tv_usec=1434}) = 0 (Timeout)
kill(9505, 0)                           = 0
select(4, [3], NULL, NULL, {tv_sec=0, tv_usec=10000}) = 0 (Timeout)
kill(9505, 0)                           = 0
select(4, [3], NULL, NULL, {tv_sec=0, tv_usec=10000}) = 0 (Timeout)
kill(9505, 0)                           = 0
select(4, [3], NULL, NULL, {tv_sec=0, tv_usec=10000}) = 0 (Timeout)
kill(9505, 0)                           = 0

The above repeats forever. Relevant processes are:

$ pstree -s 9505
systemd───systemd───conmon───bash

$ ps aux | egrep '(crun|podman|conmon)'
nmccallu    9448  0.0  0.3 1000924 57424 pts/0   Sl+  10:59   0:00 podman run --rm -it fedora:latest
nmccallu    9458  0.5  0.6 1148552 103376 pts/0  Sl+  10:59   0:08 podman run --rm -it fedora:latest
nmccallu    9461  0.0  0.0      0     0 ?        Zs   10:59   0:00 [podman] <defunct>
nmccallu    9462  0.0  0.2  78248 35652 ?        S    10:59   0:00 podman
nmccallu    9499  0.0  0.0  80400  2092 ?        Ssl  10:59   0:00 /usr/libexec/podman/conmon --api-version 1 -s -c 5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241 -u 5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241 -r /usr/bin/crun -b /var/home/nmccallu/.local/share/containers/storage/overlay-containers/5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241/userdata -p /run/user/16827/overlay-containers/5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241/userdata/pidfile -l k8s-file:/var/home/nmccallu/.local/share/containers/storage/overlay-containers/5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241/userdata/ctr.log --exit-dir /run/user/16827/libpod/tmp/exits --socket-dir-path /run/user/16827/libpod/tmp/socket --log-level error -t --conmon-pidfile /run/user/16827/overlay-containers/5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241/userdata/conmon.pid --exit-command /usr/bin/podman --exit-command-arg --root --exit-command-arg /var/home/nmccallu/.local/share/containers/storage --exit-command-arg --runroot --exit-command-arg /run/user/16827 --exit-command-arg --log-level --exit-command-arg error --exit-command-arg --cgroup-manager --exit-command-arg systemd --exit-command-arg --tmpdir --exit-command-arg /run/user/16827/libpod/tmp --exit-command-arg --runtime --exit-command-arg crun --exit-command-arg --storage-driver --exit-command-arg overlay --exit-command-arg --storage-opt --exit-command-arg overlay.mount_program=/usr/bin/fuse-overlayfs --exit-command-arg --events-backend --exit-command-arg journald --exit-command-arg container --exit-command-arg cleanup --exit-command-arg --rm --exit-command-arg 5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241
nmccallu    9511  0.3  0.0   6308  1556 pts/0    S+   10:59   0:05 /usr/bin/crun start 5e4e43c68cca9024133e9e161cae0a3e193d655c1579627c5849ec80a863f241
nmccallu   10159  0.0  0.0 216116   892 pts/1    S+   11:26   0:00 grep -E --color=auto (crun|podman|conmon)