on-smash canary detection

In addition to detect dead canary, we try to detect the very moment
when we smash the stack top.  Requested by k0kubun:
https://twitter.com/k0kubun/status/1085180749899194368


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66981 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 0 deletions

diff --git a/vm_args.c b/vm_args.c
index 0b99fdece4..932c3b75b5 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -525,6 +525,7 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
     VALUE * const orig_sp = ec->cfp->sp;
     unsigned int i;
 
+    vm_check_canary(ec, orig_sp);
     /*
      * Extend SP for GC.
      *
@@ -782,6 +783,7 @@ vm_caller_setup_arg_splat(rb_control_frame_t *cfp, struct rb_calling_info *calli
     VALUE *argv = cfp->sp - argc;
     VALUE ary = argv[argc-1];
 
+    vm_check_canary(GET_EC(), cfp->sp);
     cfp->sp--;
 
     if (!NIL_P(ary)) {