diff --git a/vm/callstack.cpp b/vm/callstack.cpp
index a0bbae8709..134a7c78b2 100755
--- a/vm/callstack.cpp
+++ b/vm/callstack.cpp
@@ -18,22 +18,6 @@ callstack *factor_vm::allot_callstack(cell size)
 	return stack;
 }
 
-/* If 'stack' points into the middle of the frame, find the nearest valid stack
-pointer where we can resume execution and hope to capture the call trace without
-crashing. Also, make sure we have at least 'stack_reserved' bytes available so
-that we don't run out of callstack space while handling the error. */
-stack_frame *factor_vm::fix_callstack_top(stack_frame *stack)
-{
-	stack_frame *frame = ctx->callstack_bottom - 1;
-
-	while(frame >= stack
-		&& frame >= ctx->callstack_top
-		&& (cell)frame >= ctx->callstack_seg->start + stack_reserved)
-		frame = frame_successor(frame);
-
-	return frame + 1;
-}
-
 /* We ignore the two topmost frames, the 'callstack' primitive
 frame itself, and the frame calling the 'callstack' primitive,
 so that set-callstack doesn't get stuck in an infinite loop.
@@ -127,13 +111,6 @@ void factor_vm::set_frame_offset(stack_frame *frame, cell offset)
 		FRAME_RETURN_ADDRESS(frame,this) = entry_point + offset;
 }
 
-void factor_vm::scrub_return_address()
-{
-	stack_frame *frame = innermost_stack_frame(ctx->callstack_bottom,
-		ctx->callstack_top);
-	set_frame_offset(frame,0);
-}
-
 cell factor_vm::frame_scan(stack_frame *frame)
 {
 	switch(frame_type(frame))
diff --git a/vm/errors.cpp b/vm/errors.cpp
index f0df0acbb8..23924df4e5 100755
--- a/vm/errors.cpp
+++ b/vm/errors.cpp
@@ -125,7 +125,6 @@ void factor_vm::primitive_unimplemented()
 
 void factor_vm::memory_signal_handler_impl()
 {
-	scrub_return_address();
 	memory_protection_error(signal_fault_addr);
 }
 
@@ -136,7 +135,6 @@ void memory_signal_handler_impl()
 
 void factor_vm::synchronous_signal_handler_impl()
 {
-	scrub_return_address();
 	signal_error(signal_number);
 }
 
@@ -150,7 +148,6 @@ void factor_vm::fp_signal_handler_impl()
 	/* Clear pending exceptions to avoid getting stuck in a loop */
 	set_fpu_state(get_fpu_state());
 
-	scrub_return_address();
 	fp_trap_error(signal_fpu_status);
 }
 
diff --git a/vm/mach_signal.cpp b/vm/mach_signal.cpp
index 469b9f2ef6..1ad07791cc 100755
--- a/vm/mach_signal.cpp
+++ b/vm/mach_signal.cpp
@@ -35,7 +35,11 @@ void factor_vm::call_fault_handler(
 	MACH_THREAD_STATE_TYPE *thread_state,
 	MACH_FLOAT_STATE_TYPE *float_state)
 {
-	MACH_STACK_POINTER(thread_state) = (cell)fix_callstack_top((stack_frame *)MACH_STACK_POINTER(thread_state));
+	cell offset = MACH_STACK_POINTER(thread_state) % 16;
+	if (offset != 0)
+		fatal_error("fault in unaligned frame with offset", offset);
+	MACH_STACK_POINTER(thread_state) -= sizeof(cell);
+	*(cell*)MACH_STACK_POINTER(thread_state) = MACH_PROGRAM_COUNTER(thread_state);
 
 	ctx->callstack_top = (stack_frame *)MACH_STACK_POINTER(thread_state);
 
diff --git a/vm/os-unix.cpp b/vm/os-unix.cpp
index a198f10a1e..efd3e03bb2 100755
--- a/vm/os-unix.cpp
+++ b/vm/os-unix.cpp
@@ -138,7 +138,12 @@ void code_heap::unguard_safepoint()
 
 void factor_vm::dispatch_signal(void *uap, void (handler)())
 {
-	UAP_STACK_POINTER(uap) = (UAP_STACK_POINTER_TYPE)fix_callstack_top((stack_frame *)UAP_STACK_POINTER(uap));
+	cell sp = (cell)UAP_STACK_POINTER(uap);
+	cell offset = sp % 16;
+	if (offset != 0)
+		fatal_error("fault in unaligned frame with offset", offset);
+	UAP_STACK_POINTER(uap) = (UAP_STACK_POINTER_TYPE)(sp - sizeof(cell));
+	*(cell*)(UAP_STACK_POINTER(uap)) = (cell)UAP_PROGRAM_COUNTER(uap);
 	UAP_PROGRAM_COUNTER(uap) = (cell)FUNCTION_CODE_POINTER(handler);
 	UAP_SET_TOC_POINTER(uap, (cell)FUNCTION_TOC_POINTER(handler));
 	ctx->callstack_top = (stack_frame *)UAP_STACK_POINTER(uap);