cgroup: only install cgroup release agent when we own the root cgroup

If we run in a container we shouldn't patch around this, and most likely
we can't anyway, and there's not much point in complaining about this.
Hence let's strictly say: the agent is private property of the host's
system instance, nothing else.

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 815fca2..4ce6c9f 100644 (file)
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -2372,7 +2372,7 @@ int manager_setup_cgroup(Manager *m) {
 
                 (void) sd_event_source_set_description(m->cgroup_inotify_event_source, "cgroup-inotify");
 
-        } else if (MANAGER_IS_SYSTEM(m) && !MANAGER_IS_TEST_RUN(m)) {
+        } else if (MANAGER_IS_SYSTEM(m) && manager_owns_root_cgroup(m) && !MANAGER_IS_TEST_RUN(m)) {
 
                 /* On the legacy hierarchy we only get notifications via cgroup agents. (Which isn't really reliable,
                  * since it does not generate events when control groups with children run empty. */