read-only filesystem, warnings and errors on try.diffoscope.org

https://try.diffoscope.org/begxazgzcvcs

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WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap. mktemp: failed to create file via template ‘/tmp/vmlinux-XXX’: Read-only file system /srv/diffoscope/diffoscope/scripts/extract-vmlinux: 33: cannot create : Directory nonexistent