core/cgroup: thaw slice of unit when thawing unit

This ensures starting a new unit under a frozen slice work as expected.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 1e9cb758de..9abcfe2b56 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -4175,9 +4175,23 @@ int unit_cgroup_freezer_action(Unit *u, FreezerAction action) {
         if (!cg_freezer_supported())
                 return 0;
 
+        /* Ignore all requests to thaw init.scope or -.slice and reject all requests to freeze them */
+        if (unit_has_name(u, SPECIAL_ROOT_SLICE) || unit_has_name(u, SPECIAL_INIT_SCOPE))
+                return action == FREEZER_FREEZE ? -EPERM : 0;
+
         if (!u->cgroup_realized)
                 return -EBUSY;
 
+        if (action == FREEZER_THAW) {
+                Unit *slice = UNIT_GET_SLICE(u);
+
+                if (slice) {
+                        r = unit_cgroup_freezer_action(slice, FREEZER_THAW);
+                        if (r < 0)
+                                return log_unit_error_errno(u, r, "Failed to thaw slice %s of unit: %m", slice->id);
+                }
+        }
+
         target = action == FREEZER_FREEZE ? FREEZER_FROZEN : FREEZER_RUNNING;
 
         r = unit_freezer_state_kernel(u, &kernel);