kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener()

For registering in add_del_listener(), when kmalloc_node() fails, need
return -ENOMEM instead of success code, and cmd_attr_register_cpumask()
wants to know about it.

After modification, give a simple common test "build -> boot up ->
kernel/controllers/cgroup/getdelays by LTP tools".

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/taskstats.c

@@ -290,6 +290,7 @@ static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
 	struct listener_list *listeners;
 	struct listener *s, *tmp, *s2;
 	unsigned int cpu;
+	int ret = 0;
 
 	if (!cpumask_subset(mask, cpu_possible_mask))
 		return -EINVAL;
@@ -304,9 +305,10 @@ static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
 		for_each_cpu(cpu, mask) {
 			s = kmalloc_node(sizeof(struct listener),
 					GFP_KERNEL, cpu_to_node(cpu));
-			if (!s)
+			if (!s) {
+				ret = -ENOMEM;
 				goto cleanup;
-
+			}
 			s->pid = pid;
 			s->valid = 1;
 
@@ -339,7 +341,7 @@ cleanup:
 		}
 		up_write(&listeners->sem);
 	}
-	return 0;
+	return ret;
 }
 
 static int parse(struct nlattr *na, struct cpumask *mask)