core: disable event sources before unreffing them

This mirrors the change done for systemd-resolved in
97935302283729c9206b84f5e00b1aff0f78ad19. Quoting that patch:

> We generally operate on the assumption that a source is "gone" as soon as we
> unref it. This is generally true because we have the only reference. But if
> something else holds the reference, our unref doesn't really stop the source
> and it could fire again.

In particular, we take temporary references from sd-event code, and when called
from an sd-event callback, we could temporarily see this elevated reference
count. This patch doesn't seem to change anything, but I think it's nicer to do
the same change as in other places and not rely on _unref() immediately
disabling the source.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/core/scope.c b/src/core/scope.c
index a247da206f..af6311bb5f 100644
--- a/src/core/scope.c
+++ b/src/core/scope.c
@@ -48,7 +48,7 @@ static void scope_done(Unit *u) {
         s->controller = mfree(s->controller);
         s->controller_track = sd_bus_track_unref(s->controller_track);
 
-        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+        s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
 }
 
 static int scope_arm_timer(Scope *s, usec_t usec) {
@@ -92,7 +92,7 @@ static void scope_set_state(Scope *s, ScopeState state) {
         s->state = state;
 
         if (!IN_SET(state, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
-                s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+                s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
 
         if (IN_SET(state, SCOPE_DEAD, SCOPE_FAILED)) {
                 unit_unwatch_all_pids(UNIT(s));