diff --git a/src/c/alloc_2.d b/src/c/alloc_2.d
index 84edde4d4..f026bc56e 100644
--- a/src/c/alloc_2.d
+++ b/src/c/alloc_2.d
@@ -32,9 +32,10 @@ struct typemanager tm_table[(int)t_end];
 static void
 finalize(cl_object o, cl_object data)
 {
+	CL_NEWENV_BEGIN {
 	switch (type_of(o)) {
 #ifdef ENABLE_DLOPEN
-	case t_codeblock:
+	case t_codeblock: {
 		cl_mapc(2, @'si::unlink-symbol', o->cblock.links);
 		if (o->cblock.handle != NULL) {
 			printf("\n;;; Freeing library %s\n", o->cblock.name?
@@ -46,13 +47,14 @@ finalize(cl_object o, cl_object data)
 #endif
 		break;
 #endif
+	}
 	case t_stream:
 		if (o->stream.file != NULL)
 			fclose(o->stream.file);
 		o->stream.file = NULL;
 		break;
-	default:
-	}
+	default:}
+	} CL_NEWENV_END;
 }
 
 cl_object
diff --git a/src/c/gbc.d b/src/c/gbc.d
index 42fb3495b..d83368742 100644
--- a/src/c/gbc.d
+++ b/src/c/gbc.d
@@ -17,6 +17,7 @@
 #include "ecl.h"
 #include "page.h"
 #include "internal.h"
+#include "bytecodes.h"
 
 #ifndef GBC_BOEHM
 
@@ -331,7 +332,7 @@ BEGIN:
 		mark_object(x->bytecodes.lex);
 		mark_object(x->bytecodes.specials);
 		mark_object(x->bytecodes.definition);
-		mark_contblock(x->bytecodes.code, x->bytecodes.code_size);
+		mark_contblock(x->bytecodes.code, x->bytecodes.code_size * sizeof(cl_opcode));
 		p = x->bytecodes.data;
 		i = x->bytecodes.data_size;
 		goto MARK_DATA;
@@ -692,6 +693,8 @@ ecl_gc(cl_type t)
   if (!GC_enabled())
     return;
 
+  CL_SAVE_ENVIRONMENT;
+
   if (SYM_VAL(@'si::*gc-verbose*') != Cnil) {
     printf("\n[GC ..");
     /* To use this should add entries in tm_table for reloc and contig.
@@ -827,6 +830,8 @@ ecl_gc(cl_type t)
     if (GC_exit_hook != NULL)
       (*GC_exit_hook)();
 
+    CL_RESTORE_ENVIRONMENT;
+
 #ifdef THREADS
 
     /* 
diff --git a/src/h/stacks.h b/src/h/stacks.h
index 463457b39..ba165194a 100644
--- a/src/h/stacks.h
+++ b/src/h/stacks.h
@@ -231,6 +231,14 @@ extern cl_object lex_env;
  * HIGH LEVEL CONTROL STRUCTURES *
  *********************************/
 
+#define CL_NEWENV_BEGIN {\
+	int __i = cl_stack_push_values(); \
+	cl_object __env = lex_env;
+
+#define CL_NEWENV_END \
+	cl_stack_pop_values(__i); \
+	lex_env = __env; }
+
 #define CL_UNWIND_PROTECT_BEGIN {\
 	bool __unwinding; frame_ptr __next_fr; \
 	cl_index __nr; \