core: do not spawn jobs or touch other units during coldplugging

Because the order of coldplugging is not defined, we can reference a
not-yet-coldplugged unit and read its state while it has not yet been
set to a meaningful value.

This way, already active units may get started again.

We fix this by deferring such actions until all units have been at
least somehow coldplugged.

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=88401

1 files changed, 16 insertions, 9 deletions

diff --git a/src/core/unit.c b/src/core/unit.c
index b639d686ad..ec4fa82ec1 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2856,27 +2856,34 @@ int unit_add_node_link(Unit *u, const char *what, bool wants) {
         return 0;
 }
 
-int unit_coldplug(Unit *u) {
+static int unit_add_deserialized_job_coldplug(Unit *u) {
+        int r;
+
+        r = manager_add_job(u->manager, u->deserialized_job, u, JOB_IGNORE_REQUIREMENTS, false, NULL, NULL);
+        if (r < 0)
+                return r;
+
+        u->deserialized_job = _JOB_TYPE_INVALID;
+
+        return 0;
+}
+
+int unit_coldplug(Unit *u, Hashmap *deferred_work) {
         int r;
 
         assert(u);
 
         if (UNIT_VTABLE(u)->coldplug)
-                if ((r = UNIT_VTABLE(u)->coldplug(u)) < 0)
+                if ((r = UNIT_VTABLE(u)->coldplug(u, deferred_work)) < 0)
                         return r;
 
         if (u->job) {
                 r = job_coldplug(u->job);
                 if (r < 0)
                         return r;
-        } else if (u->deserialized_job >= 0) {
+        } else if (u->deserialized_job >= 0)
                 /* legacy */
-                r = manager_add_job(u->manager, u->deserialized_job, u, JOB_IGNORE_REQUIREMENTS, false, NULL, NULL);
-                if (r < 0)
-                        return r;
-
-                u->deserialized_job = _JOB_TYPE_INVALID;
-        }
+                hashmap_put(deferred_work, u, &unit_add_deserialized_job_coldplug);
 
         return 0;
 }