sgi-xpc: Remove NULL pointer dereference.

If the bte copy fails, the attempt to retrieve payloads merely returns a
null pointer deref and not NULL as was expected.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index 7aafb8a91945..7d05fb5f4fee 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/drivers/misc/sgi-xp/xpc_sn2.c
@@ -1957,11 +1957,13 @@ xpc_get_deliverable_payload_sn2(struct xpc_channel *ch)
 
                         msg = xpc_pull_remote_msg_sn2(ch, get);
 
-                        DBUG_ON(msg != NULL && msg->number != get);
-                        DBUG_ON(msg != NULL && (msg->flags & XPC_M_SN2_DONE));
-                        DBUG_ON(msg != NULL && !(msg->flags & XPC_M_SN2_READY));
+                        if (msg != NULL) {
+                                DBUG_ON(msg->number != get);
+                                DBUG_ON(msg->flags & XPC_M_SN2_DONE);
+                                DBUG_ON(!(msg->flags & XPC_M_SN2_READY));
 
-                        payload = &msg->payload;
+                                payload = &msg->payload;
+                        }
                         break;
                 }