[LTP] [PATCH] [LTP v2] controllers/cgroup: Skip regression test on cgroup v2 systems

[Samir]

The cgroup_regression_test.sh test2 attempts to mount a cgroup
filesystem and expects a cgroup v1 hierarchy. On systems using
cgroup v2 (unified hierarchy), the test fails with:

  TFAIL: Failed to mount cgroup filesystem

because the legacy cgroup v1 mount layout is not available.
Use the cgroup_lib.sh helpers to detect the cgroup version:

  cgroup_require "memory"
  cgroup_version=$(cgroup_get_version "memory")

If the memory controller is on a cgroup v2 hierarchy, mark the
test as TCONF since it is only applicable to cgroup v1.

This avoids false failures when running the controllers suite
on systems where cgroup v2 is enabled.

Changelog:
V2 -> V2
1. Use cgroup_lib.sh helpers to detect the cgroup version instead of relying on the /sys/fs/cgroup/cgroup.controllers file check.
Older Patch link: https://lore.kernel.org/ltp/20260316115800.GA311158@pevik/T/#mc4b1bb1d0f73d0267a74f3de9764fa8fb398eecc

Signed-off-by: Samir <samir@linux.ibm.com>
---
 .../controllers/cgroup/cgroup_regression_test.sh      | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/testcases/kernel/controllers/cgroup/cgroup_regression_test.sh b/testcases/kernel/controllers/cgroup/cgroup_regression_test.sh
index 276231fe8..cc8fa1f99 100755
--- a/testcases/kernel/controllers/cgroup/cgroup_regression_test.sh
+++ b/testcases/kernel/controllers/cgroup/cgroup_regression_test.sh
@@ -117,6 +117,17 @@ test2()
 {
 	local val1
 	local val2
+	local cgroup_version
+	
+	# This test is specific to cgroup v1
+	# Use cgroup_lib.sh standard way for version check
+	cgroup_require "memory"
+	cgroup_version=$(cgroup_get_version "memory")
+	if [ "$cgroup_version" = "2" ]; then
+		tst_res TCONF "This test requires cgroup v1, but system is using cgroup v2"
+		cgroup_cleanup
+		return
+	fi
 
 	mount -t cgroup -o none,name=foo cgroup cgroup/
 	if [ $? -ne 0 ]; then
-- 
2.51.0