diff --git a/arch/x86/kernel/ds.c b/arch/x86/kernel/ds.c
index 1c5ca4d187877544dc4838f39ee31ae8d0493448..dcd918c1580dfda5dc66c50d3d9d3492dde6fcee 100644
--- a/arch/x86/kernel/ds.c
+++ b/arch/x86/kernel/ds.c
@@ -223,7 +223,7 @@ int ds_free(void **dsp)
 	if (*dsp)
 		kfree((void *)get_bts_buffer_base(*dsp));
 	kfree(*dsp);
-	*dsp = 0;
+	*dsp = NULL;
 
 	return 0;
 }