diff -up mdadm-3.2.6/util.c.cgroup mdadm-3.2.6/util.c
--- mdadm-3.2.6/util.c.cgroup	2012-11-15 16:48:03.327035349 -0500
+++ mdadm-3.2.6/util.c	2012-11-15 17:07:16.628751041 -0500
@@ -1611,6 +1611,25 @@ int mdmon_running(int devnum)
 	return 0;
 }
 
+int set_cgroup(char *group)
+{
+	char pid[8];
+	char pathbuf[PATH_MAX];
+	int tasks_fd, n;
+
+	snprintf(pathbuf, PATH_MAX, "/sys/fs/cgroup/%s/tasks", group);
+	tasks_fd = open(pathbuf, O_WRONLY);
+	if (tasks_fd >= 0) {
+		snprintf(pid, sizeof(pid), "%d", getpid());
+		n = write(tasks_fd, pid, strlen(pid));
+		close(tasks_fd);
+		if (n != (int)strlen(pid)) {
+			return -1;
+		}
+	}
+	return 0;
+}
+
 int start_mdmon(int devnum)
 {
 	int i, skipped;
@@ -1653,6 +1668,7 @@ int start_mdmon(int devnum)
 
 		for (i=0; paths[i]; i++)
 			if (paths[i][0]) {
+				set_cgroup("systemd");
 				if (__offroot) {
 					execl(paths[i], "mdmon", "--offroot",
 					      devnum2devname(devnum),