From 3700206f6a3c02f373caa0889edb5d3788e67830 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 8 Jun 2023 11:11:49 +0200
Subject: [PATCH] core: do not GC units/jobs that are in the D-Bus queue

Let's make sure that D-Bus messages are always sent out when pending,
before we might GC a unit/job.

This is kinda a follow-up for 8db998981a4fefd0122bcf5f965726b63c9045c2,
and a similar logic really applies: GC should only be done if we
processed everything else, generated evertyhing else and really don't
need it anymore.

(cherry picked from commit af05bb971731fe7280e4e85fde71c2e671772c18)

Related: RHEL-55301
---
 src/core/dbus-job.c  | 3 +++
 src/core/dbus-unit.c | 3 +++
 src/core/job.c       | 4 ++++
 src/core/unit.c      | 4 ++++
 4 files changed, 14 insertions(+)

diff --git a/src/core/dbus-job.c b/src/core/dbus-job.c
index 9792a5c44a1..c88d8c2dd5f 100644
--- a/src/core/dbus-job.c
+++ b/src/core/dbus-job.c
@@ -241,6 +241,9 @@ void bus_job_send_change_signal(Job *j) {
         if (j->in_dbus_queue) {
                 LIST_REMOVE(dbus_queue, j->manager->dbus_job_queue, j);
                 j->in_dbus_queue = false;
+
+                /* The job might be good to be GC once its pending signals have been sent */
+                job_add_to_gc_queue(j);
         }
 
         r = bus_foreach_bus(j->manager, j->bus_track, j->sent_dbus_new_signal ? send_changed_signal : send_new_signal, j);
diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index b45b3fdb538..9d3c3be4e99 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -1629,6 +1629,9 @@ void bus_unit_send_change_signal(Unit *u) {
         if (u->in_dbus_queue) {
                 LIST_REMOVE(dbus_queue, u->manager->dbus_unit_queue, u);
                 u->in_dbus_queue = false;
+
+                /* The unit might be good to be GC once its pending signals have been sent */
+                unit_add_to_gc_queue(u);
         }
 
         if (!u->id)
diff --git a/src/core/job.c b/src/core/job.c
index 032554a0ac5..bd3a741ffdf 100644
--- a/src/core/job.c
+++ b/src/core/job.c
@@ -1407,6 +1407,10 @@ bool job_may_gc(Job *j) {
         if (!UNIT_VTABLE(j->unit)->gc_jobs)
                 return false;
 
+        /* Make sure to send out pending D-Bus events before we unload the unit */
+        if (j->in_dbus_queue)
+                return false;
+
         if (sd_bus_track_count(j->bus_track) > 0)
                 return false;
 
diff --git a/src/core/unit.c b/src/core/unit.c
index 4360351bd98..03eb3aaecf7 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -423,6 +423,10 @@ bool unit_may_gc(Unit *u) {
         if (u->in_cgroup_empty_queue || u->in_cgroup_oom_queue)
                 return false;
 
+        /* Make sure to send out D-Bus events before we unload the unit */
+        if (u->in_dbus_queue)
+                return false;
+
         if (sd_bus_track_count(u->bus_track) > 0)
                 return false;