cgexec fails on impish, group2 support seems lacking

[Colin Ian King]

I can't get cgexec to work in impish

impish using cgroup2 fs semantics:

# mkdir /sys/fs/cgroup/test
# echo 1000000000 > /sys/fs/cgroup/test/memory.low
# cgexec -g memory:test /bin/true
libcroup initialization failed: Cgroup is not mounted
# echo $?
81

hirsute, using cgroup1 fs semantics this works OK:
# mkdir /sys/fs/cgroup/memory/test
# echo 1000000000 > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
# cgexec -g memory:test /bin/true
# echo $?
0

[Colin Ian King (colin-king)]

This is *not* a 5.13 kernel issue in Impish. I booted Hirsute with the Impish 5.13.0-14-generic kernel and the cgexec works fine in Hirsute with the 5.13 kernel.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Alex DeLorenzo (alex-delorenzo)]

Impish is using libcgroup v0.44. Support for cgroup v2 in cgexec, cgcreate, etc was added to libcgroup v2.0 on May 6, 2021 as per the release notes here[1].

I can confirm that cgcreate, cgexec, etc and other tools do not work on Impish, and fail upon execution with the same error that the OP reported.

I installed the libcgroup 2.0-2 deb from Jammy found here[2], and cgcreate, cgexec, etc now all work on Impish.

[1] https://github.com/libcgroup/libcgroup/releases/tag/v2.0

[2] https://launchpad.net/ubuntu/+source/libcgroup/2.0-2