From: Eric Dumazet <edumazet@google.com>
Date: Thu, 30 Apr 2026 02:36:25 +0000 (+0000)
Subject: net/sched: propagate tc_fill_tclass() error
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=db6ac77b0433d18248280592940849357d4f6dbd;p=thirdparty%2Flinux.git

net/sched: propagate tc_fill_tclass() error

Change tc_fill_tclass() to return -EMSGSIZE when skb is too small.

Change its caller to propagate this error (instead of -EINVAL)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260430023628.3216283-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index ed869a5ffc73..32ccd4672083 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1987,15 +1987,16 @@ static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
 out_nlmsg_trim:
 nla_put_failure:
 	nlmsg_trim(skb, b);
-	return -1;
+	return -EMSGSIZE;
 }
 
 static int tclass_notify(struct net *net, struct sk_buff *oskb,
 			 struct nlmsghdr *n, struct Qdisc *q,
 			 unsigned long cl, int event, struct netlink_ext_ack *extack)
 {
-	struct sk_buff *skb;
 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+	struct sk_buff *skb;
+	int ret;
 
 	if (!rtnl_notify_needed(net, n->nlmsg_flags, RTNLGRP_TC))
 		return 0;
@@ -2004,9 +2005,10 @@ static int tclass_notify(struct net *net, struct sk_buff *oskb,
 	if (!skb)
 		return -ENOBUFS;
 
-	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event, extack) < 0) {
+	ret = tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event, extack);
+	if (ret < 0) {
 		kfree_skb(skb);
-		return -EINVAL;
+		return ret;
 	}
 
 	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
@@ -2017,17 +2019,19 @@ static int tclass_get_notify(struct net *net, struct sk_buff *oskb,
 			     struct nlmsghdr *n, struct Qdisc *q,
 			     unsigned long cl, struct netlink_ext_ack *extack)
 {
-	struct sk_buff *skb;
 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+	struct sk_buff *skb;
+	int ret;
 
 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (!skb)
 		return -ENOBUFS;
 
-	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, RTM_NEWTCLASS,
-			   extack) < 0) {
+	ret = tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
+			     RTM_NEWTCLASS, extack);
+	if (ret < 0) {
 		kfree_skb(skb);
-		return -EINVAL;
+		return ret;
 	}
 
 	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
@@ -2041,7 +2045,7 @@ static int tclass_del_notify(struct net *net,
 			     struct netlink_ext_ack *extack)
 {
 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
 	int err = 0;
 
 	if (!cops->delete)
@@ -2052,13 +2056,12 @@ static int tclass_del_notify(struct net *net,
 		if (!skb)
 			return -ENOBUFS;
 
-		if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
-				   RTM_DELTCLASS, extack) < 0) {
+		err = tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
+				     RTM_DELTCLASS, extack);
+		if (err < 0) {
 			kfree_skb(skb);
-			return -EINVAL;
+			return err;
 		}
-	} else {
-		skb = NULL;
 	}
 
 	err = cops->delete(q, cl, extack);