tests/int/cgroups.bats: exclude dmem controller

[kolyshkin]

The dmem controller is added into kernel v6.13 and is now enabled in
Fedora 42 kernels. Yet, systemd is not aware of dmem.

This fixes the test case failure on Fedora.

For the initial test case, see commit 2751571.

For earlier commits similar to this one, see
commits 601cf58, 0527271, e83ca51.

[kolyshkin]

The alternative to this is to list all controllers known to systemd (rather than the ones that are unknown).

[thaJeztah]

Some failure on Ubuntu;

ok 305 update memory vs CheckBeforeUpdate
not ok 306 update per-device iops/bps values
# (in test file tests/integration/update.bats, line 917)
#   `[ "$status" -eq 0 ]' failed
# runc spec (status=0):
#
# runc run -d --console-socket /tmp/bats-run-HYS9G4/runc.3xTkz8/tty/sock test_update (status=1):
# time="2025-07-14T22:19:14Z" level=error msg="runc run failed: unable to start container process: error during container init: error setting cgroup config for procHooks process: failed to write \"259:0 rbps=485760\": write /sys/fs/cgroup/runc-cgroups-integration-test/test-cgroup-27654/io.max: no such device"
# --- teardown ---

[thaJeztah]

LGTM

[kolyshkin]

Some failure on Ubuntu;

ok 305 update memory vs CheckBeforeUpdate
not ok 306 update per-device iops/bps values
# (in test file tests/integration/update.bats, line 917)
#   `[ "$status" -eq 0 ]' failed
# runc spec (status=0):
#
# runc run -d --console-socket /tmp/bats-run-HYS9G4/runc.3xTkz8/tty/sock test_update (status=1):
# time="2025-07-14T22:19:14Z" level=error msg="runc run failed: unable to start container process: error during container init: error setting cgroup config for procHooks process: failed to write \"259:0 rbps=485760\": write /sys/fs/cgroup/runc-cgroups-integration-test/test-cgroup-27654/io.max: no such device"
# --- teardown ---

This appears to be a new flake :( but is def unrelated to the fix.

[kolyshkin]

Some failure on Ubuntu;

ok 305 update memory vs CheckBeforeUpdate
not ok 306 update per-device iops/bps values
# (in test file tests/integration/update.bats, line 917)
#   `[ "$status" -eq 0 ]' failed
# runc spec (status=0):
#
# runc run -d --console-socket /tmp/bats-run-HYS9G4/runc.3xTkz8/tty/sock test_update (status=1):
# time="2025-07-14T22:19:14Z" level=error msg="runc run failed: unable to start container process: error during container init: error setting cgroup config for procHooks process: failed to write \"259:0 rbps=485760\": write /sys/fs/cgroup/runc-cgroups-integration-test/test-cgroup-27654/io.max: no such device"
# --- teardown ---

This appears to be a new flake :( but is def unrelated to the fix.

Being fixed in #4807, PTAL

[kolyshkin]

Backports:

• 1.2: [1.2] tests/int/cgroups.bats: exclude dmem controller #4811
• 1.3: [1.3] tests/int/cgroups.bats: exclude dmem controller #4810