diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index f319fd1a6de3..cc4237c57cbe 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -677,7 +677,6 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 {
 	struct kernfs_open_file *of = m->private;
 	enum resctrl_res_level resid;
-	struct rdt_l3_mon_domain *d;
 	struct rdt_domain_hdr *hdr;
 	struct rmid_read rr = {0};
 	struct rdtgroup *rdtgrp;
@@ -705,6 +704,13 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 	r = resctrl_arch_get_resource(resid);
 
 	if (md->sum) {
+		struct rdt_l3_mon_domain *d;
+
+		if (WARN_ON_ONCE(resid != RDT_RESOURCE_L3)) {
+			ret = -EINVAL;
+			goto out;
+		}
+
 		/*
 		 * This file requires summing across all domains that share
 		 * the L3 cache id that was provided in the "domid" field of the
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 0110d1175398..50d88e91e0da 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -92,8 +92,8 @@ extern struct mon_evt mon_event_all[QOS_NUM_EVENTS];
  * @list:            Member of the global @mon_data_kn_priv_list list.
  * @rid:             Resource id associated with the event file.
  * @evt:             Event structure associated with the event file.
- * @sum:             Set when event must be summed across multiple
- *                   domains.
+ * @sum:             Set for RDT_RESOURCE_L3 when event must be summed
+ *                   across multiple domains.
  * @domid:           When @sum is zero this is the domain to which
  *                   the event file belongs. When @sum is one this
  *                   is the id of the L3 cache that all domains to be
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index a06cefd2a09e..a2ad99acedd6 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -3096,7 +3096,8 @@ static void rmdir_all_sub(void)
  * @rid:    The resource id for the event file being created.
  * @domid:  The domain id for the event file being created.
  * @mevt:   The type of event file being created.
- * @do_sum: Whether SNC summing monitors are being created.
+ * @do_sum: Whether SNC summing monitors are being created. Only set
+ *	    when @rid == RDT_RESOURCE_L3.
  */
 static struct mon_data *mon_get_kn_priv(enum resctrl_res_level rid, int domid,
 					struct mon_evt *mevt,