diff --git a/src/bin/debug/ltrace/arch/ltrace_stub.h b/src/bin/debug/ltrace/arch/ltrace_stub.h
index 5dc83da931..9cb3ea3c8a 100644
--- a/src/bin/debug/ltrace/arch/ltrace_stub.h
+++ b/src/bin/debug/ltrace/arch/ltrace_stub.h
@@ -9,7 +9,9 @@
 extern "C" {
 
 size_t	arch_call_stub_size();
-void	arch_init_call_stub(void* stub, void* callback, void* function);
+void	arch_init_call_stub(void* stub,
+			void* (*callback)(const void* stub, const void* args),
+			void* function);
 
 }	// extern "C"
 
diff --git a/src/bin/debug/ltrace/arch/x86/arch_ltrace_stub.S b/src/bin/debug/ltrace/arch/x86/arch_ltrace_stub.S
index 78ed641675..740c5c6234 100644
--- a/src/bin/debug/ltrace/arch/x86/arch_ltrace_stub.S
+++ b/src/bin/debug/ltrace/arch/x86/arch_ltrace_stub.S
@@ -38,7 +38,9 @@ FUNCTION_END(arch_call_stub_size)
 
 
 
-// void arch_init_call_stub(void* stub, void* callback, void* function);
+// void arch_init_call_stub(void* stub,
+//		void* (*callback)(const void* stub, const void* args),
+//		void* function);
 FUNCTION(arch_init_call_stub):
 	push	%ebp
 	movl	%esp, %ebp