Merge branch 'sk-sk_forward_alloc-fixes'

Kuniyuki Iwashima says:

====================
sk->sk_forward_alloc fixes.

The first patch fixes a negative sk_forward_alloc by adding
sk_rmem_schedule() before skb_set_owner_r(), and second patch
removes an unnecessary WARN_ON_ONCE().

v2: https://lore.kernel.org/netdev/20230209013329.87879-1-kuniyu@amazon.com/
v1: https://lore.kernel.org/netdev/20230207183718.54520-1-kuniyu@amazon.com/
====================

Link: https://lore.kernel.org/r/20230210002202.81442-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

include/net/sock.h

@@ -2434,6 +2434,19 @@ static inline __must_check bool skb_set_owner_sk_safe(struct sk_buff *skb, struc
 	return false;
 }
 
+static inline struct sk_buff *skb_clone_and_charge_r(struct sk_buff *skb, struct sock *sk)
+{
+	skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
+	if (skb) {
+		if (sk_rmem_schedule(sk, skb, skb->truesize)) {
+			skb_set_owner_r(skb, sk);
+			return skb;
+		}
+		__kfree_skb(skb);
+	}
+	return NULL;
+}
+
 static inline void skb_prepare_for_gro(struct sk_buff *skb)
 {
 	if (skb->destructor != sock_wfree) {

net/caif/caif_socket.c

@@ -1015,6 +1015,7 @@ static void caif_sock_destructor(struct sock *sk)
 		return;
 	}
 	sk_stream_kill_queues(&cf_sk->sk);
+	WARN_ON_ONCE(sk->sk_forward_alloc);
 	caif_free_client(&cf_sk->layer);
 }
 

net/core/stream.c

@@ -209,7 +209,6 @@ void sk_stream_kill_queues(struct sock *sk)
 	sk_mem_reclaim_final(sk);
 
 	WARN_ON_ONCE(sk->sk_wmem_queued);
-	WARN_ON_ONCE(sk->sk_forward_alloc);
 
 	/* It is _impossible_ for the backlog to contain anything
 	 * when we get here.  All user references to this socket

net/dccp/ipv6.c

@@ -551,11 +551,9 @@ static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
 	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL);
 	/* Clone pktoptions received with SYN, if we own the req */
 	if (*own_req && ireq->pktopts) {
-		newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
+		newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
 		consume_skb(ireq->pktopts);
 		ireq->pktopts = NULL;
-		if (newnp->pktoptions)
-			skb_set_owner_r(newnp->pktoptions, newsk);
 	}
 
 	return newsk;
@@ -615,7 +613,7 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 					       --ANK (980728)
 	 */
 	if (np->rxopt.all)
-		opt_skb = skb_clone(skb, GFP_ATOMIC);
+		opt_skb = skb_clone_and_charge_r(skb, sk);
 
 	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 		if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
@@ -679,7 +677,6 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
 		if (ipv6_opt_accepted(sk, opt_skb,
 				      &DCCP_SKB_CB(opt_skb)->header.h6)) {
-			skb_set_owner_r(opt_skb, sk);
 			memmove(IP6CB(opt_skb),
 				&DCCP_SKB_CB(opt_skb)->header.h6,
 				sizeof(struct inet6_skb_parm));

net/ipv6/tcp_ipv6.c

@@ -1388,14 +1388,11 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
 
 		/* Clone pktoptions received with SYN, if we own the req */
 		if (ireq->pktopts) {
-			newnp->pktoptions = skb_clone(ireq->pktopts,
-						      sk_gfp_mask(sk, GFP_ATOMIC));
+			newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
 			consume_skb(ireq->pktopts);
 			ireq->pktopts = NULL;
-			if (newnp->pktoptions) {
+			if (newnp->pktoptions)
 				tcp_v6_restore_cb(newnp->pktoptions);
-				skb_set_owner_r(newnp->pktoptions, newsk);
-			}
 		}
 	} else {
 		if (!req_unhash && found_dup_sk) {
@@ -1467,7 +1464,7 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 					       --ANK (980728)
 	 */
 	if (np->rxopt.all)
-		opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
+		opt_skb = skb_clone_and_charge_r(skb, sk);
 
 	reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
@@ -1553,7 +1550,6 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 		if (np->repflow)
 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
-			skb_set_owner_r(opt_skb, sk);
 			tcp_v6_restore_cb(opt_skb);
 			opt_skb = xchg(&np->pktoptions, opt_skb);
 		} else {