diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index ace4abf..771af09 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -265,7 +265,7 @@
 					  struct net *net, struct sk_buff *skb,
 					  u32 portid, unsigned int group, gfp_t flags)
 {
-	if (group >= family->n_mcgrps)
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return -EINVAL;
 	group = family->mcgrp_offset + group;
 	return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
@@ -283,9 +283,6 @@
 				    struct sk_buff *skb, u32 portid,
 				    unsigned int group, gfp_t flags)
 {
-	if (group >= family->n_mcgrps)
-		return -EINVAL;
-	group = family->mcgrp_offset + group;
 	return genlmsg_multicast_netns(family, &init_net, skb,
 				       portid, group, flags);
 }
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 7dbc4f7..4518a57 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1045,7 +1045,7 @@
 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
 			    u32 portid, unsigned int group, gfp_t flags)
 {
-	if (group >= family->n_mcgrps)
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return -EINVAL;
 	group = family->mcgrp_offset + group;
 	return genlmsg_mcast(skb, portid, group, flags);
@@ -1062,7 +1062,7 @@
 	if (nlh)
 		report = nlmsg_report(nlh);
 
-	if (group >= family->n_mcgrps)
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return;
 	group = family->mcgrp_offset + group;
 	nlmsg_notify(sk, skb, portid, group, report, flags);