[GPRS] fix null pointer dereference in GMM
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index f2e5362..d05f4cd 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -419,7 +419,7 @@
 		/* FIXME: Start some timer */
 		ctx->mm_state = GMM_COMMON_PROC_INIT;
 		ctx->tlli = msgb_tlli(msg);
-		msgid2mmctx(mmctx, msg);
+		msgid2mmctx(ctx, msg);
 		break;
 	case GSM_MI_TYPE_TMSI:
 		tmsi = strtoul(mi_string, NULL, 10);
@@ -430,7 +430,7 @@
 			/* FIXME: Start some timer */
 			ctx->mm_state = GMM_COMMON_PROC_INIT;
 			ctx->tlli = msgb_tlli(msg);
-			msgid2mmctx(mmctx, msg);
+			msgid2mmctx(ctx, msg);
 		}
 		break;
 	default: