Avoid duplicated `envadjust()` of env stacks; fix #3637

1 files changed, 7 insertions, 4 deletions

diff --git a/src/vm.c b/src/vm.c
index 8b14566c1..b56da6c88 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -115,14 +115,17 @@ stack_init(mrb_state *mrb)
 }
 
 static inline void
-envadjust(mrb_state *mrb, mrb_value *oldbase, mrb_value *newbase)
+envadjust(mrb_state *mrb, mrb_value *oldbase, mrb_value *newbase, size_t size)
 {
   mrb_callinfo *ci = mrb->c->cibase;
 
   if (newbase == oldbase) return;
   while (ci <= mrb->c->ci) {
     struct REnv *e = ci->env;
-    if (e && MRB_ENV_STACK_SHARED_P(e)) {
+    mrb_value *st;
+
+    if (e && MRB_ENV_STACK_SHARED_P(e) &&
+        (st = e->stack) && oldbase <= st && st < oldbase+size) {
       ptrdiff_t off = e->stack - oldbase;
 
       e->stack = newbase + off;
@@ -164,7 +167,7 @@ stack_extend_alloc(mrb_state *mrb, int room)
     mrb_exc_raise(mrb, mrb_obj_value(mrb->stack_err));
   }
   stack_clear(&(newstack[oldsize]), size - oldsize);
-  envadjust(mrb, oldbase, newstack);
+  envadjust(mrb, oldbase, newstack, size);
   mrb->c->stbase = newstack;
   mrb->c->stack = mrb->c->stbase + off;
   mrb->c->stend = mrb->c->stbase + size;
@@ -297,7 +300,7 @@ ecall(mrb_state *mrb, int i)
   mrb_callinfo *ci = mrb->c->ci;
   mrb_value *self = mrb->c->stack;
   struct RObject *exc;
-  int cioff;
+  ptrdiff_t cioff;
 
   if (i<0) return;
   if (ci - mrb->c->cibase > MRB_FUNCALL_DEPTH_MAX) {