diff -dur -x '*~' systemd-221.orig/src/core/manager.c systemd-221/src/core/manager.c
--- systemd-221.orig/src/core/manager.c	2015-06-17 20:28:29.557344895 +0200
+++ systemd-221/src/core/manager.c	2016-10-01 11:33:10.138847360 +0200
@@ -1478,13 +1478,12 @@
         return n;
 }
 
-static void manager_invoke_notify_message(Manager *m, Unit *u, pid_t pid, char *buf, size_t n, FDSet *fds) {
+static void manager_invoke_notify_message(Manager *m, Unit *u, pid_t pid, char *buf, FDSet *fds) {
         _cleanup_strv_free_ char **tags = NULL;
 
         assert(m);
         assert(u);
         assert(buf);
-        assert(n > 0);
 
         tags = strv_split(buf, "\n\r");
         if (!tags) {
@@ -1494,8 +1493,14 @@
 
         if (UNIT_VTABLE(u)->notify_message)
                 UNIT_VTABLE(u)->notify_message(u, pid, tags, fds);
-        else
-                log_unit_debug(u, "Got notification message for unit. Ignoring.");
+        else if (_unlikely_(log_get_max_level() >= LOG_DEBUG)) {
+                _cleanup_free_ char *x = NULL, *y = NULL;
+
+                x = cescape(buf);
+                if (x)
+                        y = ellipsize(x, 20, 90);
+                log_unit_debug(u, "Got notification message \"%s\", ignoring.", strnull(y));
+        }
 }
 
 static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
@@ -1538,10 +1543,13 @@
 
                 n = recvmsg(m->notify_fd, &msghdr, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
                 if (n < 0) {
-                        if (errno == EAGAIN || errno == EINTR)
-                                break;
-
-                        return -errno;
+                        if (!IN_SET(errno, EAGAIN, EINTR))
+                                log_error("Failed to receive notification message: %m");
+                        /* It's not an option to return an error here since it
+                         * would disable the notification handler entirely. Services
+                         * wouldn't be able to send the WATCHDOG message for
+                         * example... */
+                        return 0;
                 }
 
                 CMSG_FOREACH(cmsg, &msghdr) {
@@ -1564,7 +1572,8 @@
                         r = fdset_new_array(&fds, fd_array, n_fds);
                         if (r < 0) {
                                 close_many(fd_array, n_fds);
-                                return log_oom();
+                                log_oom();
+                                return 0;
                         }
                 }
 
@@ -1578,25 +1587,27 @@
                         continue;
                 }
 
+                /* The message should be a string. Here we make sure it's NUL-terminated,
+                 * but only the part until first NUL will be used anyway. */
                 buf[n] = 0;
 
                 /* Notify every unit that might be interested, but try
                  * to avoid notifying the same one multiple times. */
                 u1 = manager_get_unit_by_pid(m, ucred->pid);
                 if (u1) {
-                        manager_invoke_notify_message(m, u1, ucred->pid, buf, n, fds);
+                        manager_invoke_notify_message(m, u1, ucred->pid, buf, fds);
                         found = true;
                 }
 
                 u2 = hashmap_get(m->watch_pids1, LONG_TO_PTR(ucred->pid));
                 if (u2 && u2 != u1) {
-                        manager_invoke_notify_message(m, u2, ucred->pid, buf, n, fds);
+                        manager_invoke_notify_message(m, u2, ucred->pid, buf, fds);
                         found = true;
                 }
 
                 u3 = hashmap_get(m->watch_pids2, LONG_TO_PTR(ucred->pid));
                 if (u3 && u3 != u2 && u3 != u1) {
-                        manager_invoke_notify_message(m, u3, ucred->pid, buf, n, fds);
+                        manager_invoke_notify_message(m, u3, ucred->pid, buf, fds);
                         found = true;
                 }
 
Only in systemd-221/src/core: manager.c.orig