Merge branch 'for-5.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fix from Tejun Heo:
 "Roman found and fixed a bug in the cgroup2 freezer which allows new
  child cgroup to escape frozen state"

* 'for-5.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: freezer: fix frozen state inheritance
  kselftests: cgroup: add freezer mkdir test

1 files changed, 54 insertions, 0 deletions

diff --git a/tools/testing/selftests/cgroup/test_freezer.c b/tools/testing/selftests/cgroup/test_freezer.c
index 8219a30853d2..0fc1b6d4b0f9 100644
--- a/tools/testing/selftests/cgroup/test_freezer.c
+++ b/tools/testing/selftests/cgroup/test_freezer.c
@@ -448,6 +448,59 @@ cleanup:
 }
 
 /*
+ * The test creates a cgroups and freezes it. Then it creates a child cgroup
+ * and populates it with a task. After that it checks that the child cgroup
+ * is frozen and the parent cgroup remains frozen too.
+ */
+static int test_cgfreezer_mkdir(const char *root)
+{
+	int ret = KSFT_FAIL;
+	char *parent, *child = NULL;
+	int pid;
+
+	parent = cg_name(root, "cg_test_mkdir_A");
+	if (!parent)
+		goto cleanup;
+
+	child = cg_name(parent, "cg_test_mkdir_B");
+	if (!child)
+		goto cleanup;
+
+	if (cg_create(parent))
+		goto cleanup;
+
+	if (cg_freeze_wait(parent, true))
+		goto cleanup;
+
+	if (cg_create(child))
+		goto cleanup;
+
+	pid = cg_run_nowait(child, child_fn, NULL);
+	if (pid < 0)
+		goto cleanup;
+
+	if (cg_wait_for_proc_count(child, 1))
+		goto cleanup;
+
+	if (cg_check_frozen(child, true))
+		goto cleanup;
+
+	if (cg_check_frozen(parent, true))
+		goto cleanup;
+
+	ret = KSFT_PASS;
+
+cleanup:
+	if (child)
+		cg_destroy(child);
+	free(child);
+	if (parent)
+		cg_destroy(parent);
+	free(parent);
+	return ret;
+}
+
+/*
  * The test creates two nested cgroups, freezes the parent
  * and removes the child. Then it checks that the parent cgroup
  * remains frozen and it's possible to create a new child
@@ -815,6 +868,7 @@ struct cgfreezer_test {
 	T(test_cgfreezer_simple),
 	T(test_cgfreezer_tree),
 	T(test_cgfreezer_forkbomb),
+	T(test_cgfreezer_mkdir),
 	T(test_cgfreezer_rmdir),
 	T(test_cgfreezer_migrate),
 	T(test_cgfreezer_ptrace),