service: make sure the watchdog timer is not restarted while stopping

A watchdog notification may be handled after the watchdog timer was stopped
while stopping the service. As a result the timer is restarted and the
service may be restarted as well.
The watchdog timestamp is initially set during startup in
service_enter_start_post() and cleared when the timer is stopped. Therefore
it can be used as an indication if the timer should be reset.

diff --git a/src/core/service.c b/src/core/service.c
index 593946e5172e61517a8d7870fb7763857ae816d3..baddc5ade4cd05cff8c8969646710e9c1af5cb4a 100644 (file)
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -3400,7 +3400,8 @@ static void service_notify_message(Unit *u, pid_t pid, char **tags) {
         if (strv_find(tags, "WATCHDOG=1")) {
                 log_debug_unit(u->id,
                                "%s: got WATCHDOG=1", u->id);
-                service_reset_watchdog(s);
+                if (dual_timestamp_is_set(&s->watchdog_timestamp))
+                        service_reset_watchdog(s);
         }
 
         /* Notify clients about changed status or main pid */