diff --git a/ch2/os/Makefile b/ch2/os/Makefile
index dccc8cc..2b314fb 100644
--- a/ch2/os/Makefile
+++ b/ch2/os/Makefile
@@ -27,7 +27,7 @@ $(KERNEL_BIN): build_elf
 	@$(OBJCOPY) $(KERNEL_ELF) --strip-all -O binary $@
 
 
-debug:build_elf $(KERNEL_BIN) $(SYMBOL_MAP) kill
+debug:build_elf $(KERNEL_BIN) $(SYMBOL_MAP)
 	$(QEMU_CMD_PATH) \
 		-machine virt \
 		-display none \