HWPOISON: Copy si_addr_lsb to user

The original hwpoison code added a new siginfo field si_addr_lsb to
pass the granuality of the fault address to user space. Unfortunately
this field was never copied to user space. Fix this here.

I added explicit checks for the MCEERR codes to avoid having
to patch all potential callers to initialize the field.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index bded65187780..919562c3d6b7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2215,6 +2215,14 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
 #ifdef __ARCH_SI_TRAPNO
                 err |= __put_user(from->si_trapno, &to->si_trapno);
 #endif
+#ifdef BUS_MCEERR_AO
+                /* 
+                 * Other callers might not initialize the si_lsb field,
+                 * so check explicitely for the right codes here.
+                 */
+                if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
+                        err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
+#endif
                 break;
         case __SI_CHLD:
                 err |= __put_user(from->si_pid, &to->si_pid);