Merge pull request #12626 from keszybz/oompolicy-check

Make the check if oom-killer fired more robust

src/core/cgroup.c

@@ -2607,7 +2607,7 @@ void unit_add_to_cgroup_empty_queue(Unit *u) {
                 log_debug_errno(r, "Failed to enable cgroup empty event source: %m");
 }
 
-static int unit_check_oom(Unit *u) {
+int unit_check_oom(Unit *u) {
         _cleanup_free_ char *oom_kill = NULL;
         bool increased;
         uint64_t c;

src/core/cgroup.h

@@ -197,6 +197,7 @@ int unit_watch_cgroup(Unit *u);
 int unit_watch_cgroup_memory(Unit *u);
 
 void unit_add_to_cgroup_empty_queue(Unit *u);
+int unit_check_oom(Unit *u);
 
 int unit_attach_pids_to_cgroup(Unit *u, Set *pids, const char *suffix_path);
 

src/core/manager.c

@@ -2524,8 +2524,13 @@ static int manager_dispatch_sigchld(sd_event_source *source, void *userdata) {
                 /* Finally, execute them all. Note that u1, u2 and the array might contain duplicates, but
                  * that's fine, manager_invoke_sigchld_event() will ensure we only invoke the handlers once for
                  * each iteration. */
-                if (u1)
+                if (u1) {
+                        /* We check for oom condition, in case we got SIGCHLD before the oom notification.
+                         * We only do this for the cgroup the PID belonged to. */
+                        (void) unit_check_oom(u1);
+
                         manager_invoke_sigchld_event(m, u1, &si);
+                }
                 if (u2)
                         manager_invoke_sigchld_event(m, u2, &si);
                 if (array_copy)

src/core/service.c

@@ -2047,9 +2047,10 @@ static int service_adverse_to_leftover_processes(Service *s) {
          * aren't as rigoriously written to protect aganst against multiple use. */
         if (unit_warn_leftover_processes(UNIT(s)) &&
             IN_SET(s->kill_context.kill_mode, KILL_MIXED, KILL_CONTROL_GROUP) &&
-            !s->kill_context.send_sigkill) {
-               return log_unit_error_errno(UNIT(s), SYNTHETIC_ERRNO(EBUSY), "Will not start SendSIGKILL=no service of type KillMode=control-group or mixed while processes exist");
-        }
+            !s->kill_context.send_sigkill)
+               return log_unit_error_errno(UNIT(s), SYNTHETIC_ERRNO(EBUSY),
+                                           "Will not start SendSIGKILL=no service of type KillMode=control-group or mixed while processes exist");
+
         return 0;
 }