diff --git a/cc/vndk.go b/cc/vndk.go
index b2614c5..2cac03c 100644
--- a/cc/vndk.go
+++ b/cc/vndk.go
@@ -62,8 +62,8 @@
 		// declared as a VNDK or VNDK-SP module. The vendor variant
 		// will be installed in /system instead of /vendor partition.
 		//
-		// `vendor_available` must be explicitly set to either true or
-		// false together with `vndk: {enabled: true}`.
+		// `vendor_available` and `product_available` must be explicitly
+		// set to either true or false together with `vndk: {enabled: true}`.
 		Enabled *bool
 
 		// declared as a VNDK-SP module, which is a subset of VNDK.
@@ -129,13 +129,16 @@
 	return "native:vendor:vndkspext"
 }
 
+// VNDK link type check from a module with UseVndk() == true.
 func (vndk *vndkdep) vndkCheckLinkType(ctx android.BaseModuleContext, to *Module, tag blueprint.DependencyTag) {
 	if to.linker == nil {
 		return
 	}
 	if !vndk.isVndk() {
-		// Non-VNDK modules (those installed to /vendor, /product, or /system/product) can't depend
-		// on modules marked with vendor_available: false.
+		// Non-VNDK modules those installed to /vendor or /system/vendor
+		// can't depend on modules marked with vendor_available: false;
+		// or those installed to /product or /system/product can't depend
+		// on modules marked with product_available: false.
 		violation := false
 		if lib, ok := to.linker.(*llndkStubDecorator); ok && !Bool(lib.Properties.Vendor_available) {
 			violation = true
@@ -174,6 +177,7 @@
 				to.Name())
 			return
 		}
+		// TODO(b/150902910): vndk-ext for product must check product_available.
 		if !Bool(to.VendorProperties.Vendor_available) {
 			ctx.ModuleErrorf(
 				"`extends` refers module %q which does not have `vendor_available: true`",
@@ -338,6 +342,8 @@
 	} else {
 		vndkCoreLibraries(mctx.Config())[name] = filename
 	}
+	// As `vendor_available` and `product_available` has the same value for VNDK modules,
+	// we don't need to check both values.
 	if !Bool(m.VendorProperties.Vendor_available) {
 		vndkPrivateLibraries(mctx.Config())[name] = filename
 	}