kselftest/cgroup: fix incorrect test_core skip

The test_core will skip the
test_cgcore_no_internal_process_constraint_on_threads test case if the
'cpu' controller missing in root's subtree_control. In fact we need to
set the 'cpu' in subtree_control, to make the testing meaningful.

./test_core
...
ok 4 # skip test_cgcore_no_internal_process_constraint_on_threads
...

Signed-off-by: Alex Shi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Claudio Zumbo <[email protected]>
Cc: Claudio <[email protected]>
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Roman Gushchin <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c
index d78f1c5366d3..79053a4f4783 100644
--- a/tools/testing/selftests/cgroup/test_core.c
+++ b/tools/testing/selftests/cgroup/test_core.c
@@ -198,7 +198,7 @@ static int test_cgcore_no_internal_process_constraint_on_threads(const char *roo
 	char *parent = NULL, *child = NULL;
 
 	if (cg_read_strstr(root, "cgroup.controllers", "cpu") ||
-	    cg_read_strstr(root, "cgroup.subtree_control", "cpu")) {
+	    cg_write(root, "cgroup.subtree_control", "+cpu")) {
 		ret = KSFT_SKIP;
 		goto cleanup;
 	}