Blackfin arch: have is_user_addr_valid() check for overflows (like when address is -1)

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/ptrace.c b/arch/blackfin/kernel/ptrace.c
index 7e1f762b6700..140bf00e9974 100644
--- a/arch/blackfin/kernel/ptrace.c
+++ b/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;