diff --git a/Makefile b/Makefile
index add32a749860..8dc6707542a8 100644
--- a/Makefile
+++ b/Makefile
@@ -782,6 +782,7 @@ KBUILD_CFLAGS += $(stackp-flags-y)
 
 ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += -Qunused-arguments
+# The kernel builds with '-std=gnu89' so use of GNU extensions is acceptable.
 KBUILD_CFLAGS += -Wno-gnu
 # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
 # source of a reference will be _MergedGlobals and not on of the whitelisted names.