diff --git a/[refs] b/[refs]
index b3b2e3125855..f11a0eea798a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d207a8c7681f14302e9e80ef5b8202abe39060b5
+refs/heads/master: 3c08f1d122627c9559fb03a11f52ea37f960b61e
diff --git a/trunk/arch/blackfin/kernel/ptrace.c b/trunk/arch/blackfin/kernel/ptrace.c
index 7e1f762b6700..140bf00e9974 100644
--- a/trunk/arch/blackfin/kernel/ptrace.c
+++ b/trunk/arch/blackfin/kernel/ptrace.c
@@ -160,6 +160,10 @@ static inline int is_user_addr_valid(struct task_struct *child,
 	struct vm_list_struct *vml;
 	struct sram_list_struct *sraml;
 
+	/* overflow */
+	if (start + len < start)
+		return -EIO;
+
 	for (vml = child->mm->context.vmlist; vml; vml = vml->next)
 		if (start >= vml->vma->vm_start && start + len < vml->vma->vm_end)
 			return 0;