[PATCH] x86_64: check if ptrace RIP is canonical

This works around an AMD Erratum.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
index e26e86bb56fe..892212161aa8 100644
--- a/arch/x86_64/kernel/ptrace.c
+++ b/arch/x86_64/kernel/ptrace.c
@@ -277,6 +277,11 @@ static int putreg(struct task_struct *child,
                                 return -EIO;
                         value &= 0xffff;
                         break;
+                case offsetof(struct user_regs_struct, rip):
+                        /* Check if the new RIP address is canonical */
+                        if (value >= TASK_SIZE)
+                                return -EIO;
+                        break;
         }
         put_stack_long(child, regno - sizeof(struct pt_regs), value);
         return 0;