diff --git a/linuxkm/Kbuild b/linuxkm/Kbuild
index 0036f7db1..69620fc2a 100644
--- a/linuxkm/Kbuild
+++ b/linuxkm/Kbuild
@@ -49,7 +49,9 @@ $(obj)/linuxkm/module_exports.o: $(WOLFSSL_OBJ_TARGETS)
 # this mechanism only works in kernel 5.x+ (fallback to hardcoded value)
 hostprogs := linuxkm/get_thread_size
 always-y := $(hostprogs)
-HOST_EXTRACFLAGS += $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CFLAGS) -static -fno-omit-frame-pointer
+# "-mindirect-branch=keep -mfunction-return=keep" to avoid "undefined reference
+#  to `__x86_return_thunk'" on CONFIG_RETHUNK kernels (5.19.0-rc7)
+HOST_EXTRACFLAGS += $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CFLAGS) -static -fno-omit-frame-pointer -mindirect-branch=keep -mfunction-return=keep
 
 # this rule is needed to get build to succeed in 4.x (get_thread_size still doesn't get built)
 $(obj)/linuxkm/get_thread_size: $(src)/linuxkm/get_thread_size.c