diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index b0b53b8..77575b3 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -156,20 +156,11 @@
 {
 	long *ptr = filp->private_data;
 	unsigned long val, flags;
-	char buf[64];
 	int ret;
 	int cpu;
 
-	if (count >= sizeof(buf))
-		return -EINVAL;
-
-	if (copy_from_user(&buf, ubuf, count))
-		return -EFAULT;
-
-	buf[count] = 0;
-
-	ret = strict_strtoul(buf, 10, &val);
-	if (ret < 0)
+	ret = kstrtoul_from_user(ubuf, count, 10, &val);
+	if (ret)
 		return ret;
 
 	local_irq_save(flags);