diff --git a/kernel/src/arch/x86_64/CPU.cpp b/kernel/src/arch/x86_64/CPU.cpp
index c1dd3e8d..b306459b 100644
--- a/kernel/src/arch/x86_64/CPU.cpp
+++ b/kernel/src/arch/x86_64/CPU.cpp
@@ -134,7 +134,7 @@ extern "C" void handle_x86_exception(Registers* regs)
     case 19: FIXME_UNHANDLED_INTERRUPT("SIMD floating-point exception");
     case 20: FIXME_UNHANDLED_INTERRUPT("Virtualization exception");
     case 21: FIXME_UNHANDLED_INTERRUPT("Control-protection exception");
-    default: FIXME_UNHANDLED_INTERRUPT("Reserved exception or #DF/#MC, which shouldn't call handle_x86_exception");
+    default: fail("Caught invalid reserved exception or #DF/#MC, which shouldn't call handle_x86_exception");
     }
 }