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, 1 insertions, 0 deletions

diff --git a/vm.c b/vm.c
index 9e7eb1dc32..bbda6ee4c0 100644
--- a/vm.c
+++ b/vm.c
@@ -1090,6 +1090,7 @@ invoke_iseq_block_from_c(rb_execution_context_t *ec, const struct rb_captured_bl
     stack_check(ec);
 
     CHECK_VM_STACK_OVERFLOW(cfp, argc);
+    vm_check_canary(ec, sp);
     cfp->sp = sp + argc;
     for (i=0; i<argc; i++) {
 	sp[i] = argv[i];