tests: add integration test for cgroups hybrid

Check that runc run and runc exec put the process on the same cgroups v2
when using hybrid mode.

Signed-off-by: Mauricio Vásquez <[email protected]>

Author: mauriciovasquezbernal

tests/integration/cgroups.bats

@@ -270,3 +270,26 @@ function setup() {
 
 	check_cpu_weight 42
 }
+
+@test "runc exec (cgroup v2 hybrid joins correct cgroup)" {
+	requires root cgroups_hybrid
+
+	set_cgroups_path "$BUSYBOX_BUNDLE"
+	set_cgroup_mount_writable "$BUSYBOX_BUNDLE"
+
+	runc run --pid-file pid.txt -d --console-socket "$CONSOLE_SOCKET" test_cgroups_group
+	[ "$status" -eq 0 ]
+
+	pid=$(cat pid.txt)
+	run_cgroup=$(tail -1 </proc/"$pid"/cgroup)
+	[[ $run_cgroup == *"runc-cgroups-integration-test"* ]]
+
+	runc exec test_cgroups_group cat /proc/self/cgroup
+	[ "$status" -eq 0 ]
+
+	exec_cgroup=${lines[-1]}
+	[[ $exec_cgroup == *"runc-cgroups-integration-test"* ]]
+
+	# check that the cgroups v2 path is the same for both processes
+	[[ "$run_cgroup" == "$exec_cgroup" ]]
+}

tests/integration/helpers.bash

@@ -151,6 +151,9 @@ function init_cgroup_paths() {
 			CGROUP_SUBSYSTEMS+=" freezer"
 		fi
 	else
+		if stat -f -c %t /sys/fs/cgroup/unified | grep -qFw 63677270; then
+			CGROUP_HYBRID=yes
+		fi
 		CGROUP_UNIFIED=no
 		CGROUP_SUBSYSTEMS=$(awk '!/^#/ {print $1}' /proc/cgroups)
 		for g in ${CGROUP_SUBSYSTEMS}; do
@@ -352,6 +355,12 @@ function requires() {
 				skip_me=1
 			fi
 			;;
+		cgroups_hybrid)
+			init_cgroup_paths
+			if [ "$CGROUP_HYBRID" != "yes" ]; then
+				skip_me=1
+			fi
+			;;
 		smp)
 			local cpu_count=$(grep -c '^processor' /proc/cpuinfo)
 			if [ "$cpu_count" -lt 2 ]; then