diff --git a/kernel/Makefile b/kernel/Makefile
index d8d33bb..d43a46f 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -26,7 +26,7 @@ export CXXFLAGS := -Wall -O2
 export LDFLAGS  := -T $(LDSCRIPT)
 
 SUBDIRS         := boot
-SUBDIRS_clean   := $(subdirs:%=%.clean)
+SUBDIRS_clean   := $(SUBDIRS:%=%.clean)
 
 .PHONY: all
 all: $(KERNEL).gz