diff --git a/Kbuild b/Kbuild
index 13a946f..57167e2 100644
--- a/Kbuild
+++ b/Kbuild
@@ -3239,6 +3239,8 @@
 
 cppflags-$(CONFIG_RX_FISA) += -DWLAN_SUPPORT_RX_FISA
 
+cppflags-$(CONFIG_RX_DEFRAG_DO_NOT_REINJECT) += -DRX_DEFRAG_DO_NOT_REINJECT
+
 cppflags-$(CONFIG_MORE_TX_DESC) += -DTX_TO_NPEERS_INC_TX_DESCS
 
 ccflags-$(CONFIG_HASTINGS_BT_WAR) += -DHASTINGS_BT_WAR