diff --git a/src/udev/udev-manager.c b/src/udev/udev-manager.c
index d218b8bef7..452a68778e 100644
--- a/src/udev/udev-manager.c
+++ b/src/udev/udev-manager.c
@@ -1312,13 +1312,17 @@ static int on_post(sd_event_source *s, void *userdata) {
         if (sd_event_source_get_pending(sd_device_monitor_get_event_source(manager->monitor)) != 0)
                 return 0;
 
+        /* We are currently synthesizing change uevents, hence new uevents may come soon. */
+        if (!set_isempty(manager->synthesize_change_child_event_sources))
+                return 0;
+
         (void) manager_unlink_queue_file(manager);
         (void) manager_reset_kill_workers_timer(manager);
 
         if (!hashmap_isempty(manager->workers))
                 return 0; /* There still exist idle workers. */
 
-        if (manager->workers_cgroup && set_isempty(manager->synthesize_change_child_event_sources))
+        if (manager->workers_cgroup)
                 /* cleanup possible left-over processes in the workers cgroup */
                 if (cg_kill_kernel_sigkill(manager->workers_cgroup, /* ret_n_pids_killed= */ NULL) == -EOPNOTSUPP)
                         (void) cg_kill(manager->workers_cgroup, SIGKILL, CGROUP_IGNORE_SELF, /* killed_pids= */ NULL, /* log_kill= */ NULL, /* userdata= */ NULL);
@@ -1379,10 +1383,21 @@ static int manager_setup_event(Manager *manager) {
         if (r < 0)
                 return log_error_errno(r, "Failed to create SIGHUP event source: %m");
 
-        r = sd_event_add_post(e, /* ret= */ NULL, on_post, manager);
+        _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
+        r = sd_event_add_post(e, &s, on_post, manager);
         if (r < 0)
                 return log_error_errno(r, "Failed to create post event source: %m");
 
+        r = sd_event_source_set_priority(s, EVENT_PRIORITY_POST);
+        if (r < 0)
+                return log_error_errno(r, "Failed to set priority to post event source: %m");
+
+        (void) sd_event_source_set_description(s, "post-event-source");
+
+        r = sd_event_source_set_floating(s, true);
+        if (r < 0)
+                return log_error_errno(r, "Failed to set floating to post event source: %m");
+
         /* Eventually, we probably want to do more here on memory pressure, for example, kill idle workers immediately */
         r = sd_event_add_memory_pressure(e, /* ret= */ NULL, /* callback= */ NULL, /* userdata= */ NULL);
         if (r < 0)
diff --git a/src/udev/udev-manager.h b/src/udev/udev-manager.h
index 9ff81acd9f..48ac3cc067 100644
--- a/src/udev/udev-manager.h
+++ b/src/udev/udev-manager.h
@@ -13,20 +13,23 @@
 /* This should have a higher priority than the device monitor and inotify watch, to make device monitor and
  * inotify event source stopped as soon as possible when the signal is received. Otherwise, we may continue
  * receive events that needs to be serialized anyway. */
-#define EVENT_PRIORITY_SIGTERM        (SD_EVENT_PRIORITY_NORMAL - 6)
+#define EVENT_PRIORITY_SIGTERM        (SD_EVENT_PRIORITY_NORMAL - 7)
 /* This must have a higher priority than the worker notification, to make IN_IGNORED event received earlier
  * than notifications about requests of adding/removing inotify watches. */
-#define EVENT_PRIORITY_INOTIFY_WATCH  (SD_EVENT_PRIORITY_NORMAL - 5)
+#define EVENT_PRIORITY_INOTIFY_WATCH  (SD_EVENT_PRIORITY_NORMAL - 6)
 /* This must have a higher priority than the worker exit event, to make notifications about completions of
  * processing events received before exit. */
-#define EVENT_PRIORITY_WORKER_NOTIFY  (SD_EVENT_PRIORITY_NORMAL - 4)
+#define EVENT_PRIORITY_WORKER_NOTIFY  (SD_EVENT_PRIORITY_NORMAL - 5)
 /* This should have a higher priority than timer events about killing long running worker processes or idle
  * worker processes. */
-#define EVENT_PRIORITY_WORKER_EXIT    (SD_EVENT_PRIORITY_NORMAL - 3)
+#define EVENT_PRIORITY_WORKER_EXIT    (SD_EVENT_PRIORITY_NORMAL - 4)
 /* As mentioned above, this should have a lower priority than the exit event source. */
-#define EVENT_PRIORITY_WORKER_TIMER   (SD_EVENT_PRIORITY_NORMAL - 2)
-/* This must have a lower priority than the worker event source. Otherwise, flood of uevents delays worker
- * sigchld events or notifications, and workers will not continue to process events. */
+#define EVENT_PRIORITY_WORKER_TIMER   (SD_EVENT_PRIORITY_NORMAL - 3)
+/* This must have a higher priority than the device monitor to prevent uevent floods from starving
+ * event_queue_start(), but lower than worker event sources to observe worker completions first. */
+#define EVENT_PRIORITY_POST           (SD_EVENT_PRIORITY_NORMAL - 2)
+/* This must have a lower priority than the worker event source and post event source. Otherwise, flood of
+ * uevents delays worker sigchld events or notifications, and workers will not continue to process events. */
 #define EVENT_PRIORITY_DEVICE_MONITOR (SD_EVENT_PRIORITY_NORMAL - 1)
 /* This should have a lower priority than most event sources, but let's process earlier than varlink and the
  * legacy control socket. */