diff --git a/system/physmem.c b/system/physmem.c
index 33d09f7571..261196cde0 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -1521,7 +1521,7 @@ static void qemu_ram_setup_dump(void *addr, ram_addr_t size)
         if (ret) {
             perror("qemu_madvise");
             fprintf(stderr, "madvise doesn't support MADV_DONTDUMP, "
-                            "but dump_guest_core=off specified\n");
+                            "but dump-guest-core=off specified\n");
         }
     }
 }