diff --git a/vm/code_block_visitor.hpp b/vm/code_block_visitor.hpp
index 50d4a96a7d..d43daa3ad3 100644
--- a/vm/code_block_visitor.hpp
+++ b/vm/code_block_visitor.hpp
@@ -24,7 +24,6 @@ template<typename Fixup> struct code_block_visitor {
 	void visit_embedded_code_pointers(code_block *compiled);
 	void visit_context_code_blocks();
 	void visit_uninitialized_code_blocks();
-	void visit_sample_callstacks();
 
 	void visit_code_roots();
 };
@@ -136,22 +135,10 @@ void code_block_visitor<Fixup>::visit_uninitialized_code_blocks()
 	parent->code->uninitialized_blocks = new_uninitialized_blocks;
 }
 
-template<typename Fixup>
-void code_block_visitor<Fixup>::visit_sample_callstacks()
-{
-	for (std::vector<code_block *>::iterator iter = parent->sample_callstacks.begin();
-		iter != parent->sample_callstacks.end();
-		++iter)
-	{
-		*iter = fixup.fixup_code(*iter);
-	}
-}
-
 template<typename Fixup>
 void code_block_visitor<Fixup>::visit_code_roots()
 {
 	visit_uninitialized_code_blocks();
-	visit_sample_callstacks();
 }
 
 }
diff --git a/vm/sampling_profiler.cpp b/vm/sampling_profiler.cpp
index 48052888fd..24ac5c8bde 100644
--- a/vm/sampling_profiler.cpp
+++ b/vm/sampling_profiler.cpp
@@ -50,7 +50,7 @@ void factor_vm::record_callstack_sample(cell *begin, cell *end)
 	stack_frame *frame = ctx->bottom_frame();
 
 	while (frame >= ctx->callstack_top) {
-		sample_callstacks.push_back(frame_code(frame));
+		sample_callstacks.push_back(frame_code(frame)->owner);
 		frame = frame_successor(frame);
 	}
 
@@ -74,7 +74,7 @@ void factor_vm::clear_samples()
 	// Swapping into temporaries releases the vector's allocated storage,
 	// whereas clear() would leave the allocation as-is
 	std::vector<profiling_sample> sample_graveyard;
-	std::vector<code_block*> sample_callstack_graveyard;
+	std::vector<cell> sample_callstack_graveyard;
 	samples.swap(sample_graveyard);
 	sample_callstacks.swap(sample_callstack_graveyard);
 }
@@ -127,14 +127,14 @@ void factor_vm::primitive_get_samples()
 			cell callstack_size = from_iter->callstack_end - from_iter->callstack_begin;
 			data_root<array> callstack(allot_array(callstack_size,false_object),this);
 
-			std::vector<code_block*>::const_iterator
+			std::vector<cell>::const_iterator
 				callstacks_begin = sample_callstacks.begin(),
 				c_from_iter = callstacks_begin + from_iter->callstack_begin,
 				c_from_iter_end = callstacks_begin + from_iter->callstack_end;
 			cell c_to_i = 0;
 
 			for (; c_from_iter != c_from_iter_end; ++c_from_iter, ++c_to_i)
-				set_array_nth(callstack.untagged(),c_to_i,(*c_from_iter)->owner);
+				set_array_nth(callstack.untagged(),c_to_i,*c_from_iter);
 
 			set_array_nth(sample.untagged(),5,callstack.value());
 
diff --git a/vm/slot_visitor.hpp b/vm/slot_visitor.hpp
index b2dd40e582..b2fd5d3c4b 100755
--- a/vm/slot_visitor.hpp
+++ b/vm/slot_visitor.hpp
@@ -134,6 +134,7 @@ template<typename Fixup> struct slot_visitor {
 	void visit_contexts();
 	void visit_code_block_objects(code_block *compiled);
 	void visit_embedded_literals(code_block *compiled);
+	void visit_sample_callstacks();
 };
 
 template<typename Fixup>
@@ -249,6 +250,17 @@ void slot_visitor<Fixup>::visit_literal_table_roots()
 	parent->code->uninitialized_blocks = new_uninitialized_blocks;
 }
 
+template<typename Fixup>
+void slot_visitor<Fixup>::visit_sample_callstacks()
+{
+	for (std::vector<cell>::iterator iter = parent->sample_callstacks.begin();
+		iter != parent->sample_callstacks.end();
+		++iter)
+	{
+		visit_handle(&*iter);
+	}
+}
+
 template<typename Fixup>
 void slot_visitor<Fixup>::visit_roots()
 {
@@ -261,6 +273,7 @@ void slot_visitor<Fixup>::visit_roots()
 	visit_bignum_roots();
 	visit_callback_roots();
 	visit_literal_table_roots();
+	visit_sample_callstacks();
 
 	visit_object_array(parent->special_objects,parent->special_objects + special_object_count);
 }
diff --git a/vm/vm.hpp b/vm/vm.hpp
index f4c765d645..08195a81e7 100755
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -75,7 +75,7 @@ struct factor_vm
 
 	/* State kept by the sampling profiler */
 	std::vector<profiling_sample> samples;
-	std::vector<code_block*> sample_callstacks;
+	std::vector<cell> sample_callstacks;
 	volatile profiling_sample_count safepoint_sample_counts;
 
 	/* GC is off during heap walking */