[PATCH 6.12 27/70] net: annotate data-races around sk->sk_{data_ready,write_space}

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 2ef2b20cf4e04ac8a6ba68493f8780776ff84300 ]

skmsg (and probably other layers) are changing these pointers
while other cpus might read them concurrently.

Add corresponding READ_ONCE()/WRITE_ONCE() annotations
for UDP, TCP and AF_UNIX.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Reported-by: syzbot+87f770387a9e5dc6b79b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/699ee9fc.050a0220.1cd54b.0009.GAE@google.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260225131547.1085509-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Leon Chen <leonchen.oss@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/core/skmsg.c         |   14 +++++++-------
 net/ipv4/tcp.c           |    4 ++--
 net/ipv4/tcp_bpf.c       |    2 +-
 net/ipv4/tcp_input.c     |   14 ++++++++------
 net/ipv4/tcp_minisocks.c |    2 +-
 net/ipv4/udp.c           |    3 ++-
 net/ipv4/udp_bpf.c       |    2 +-
 net/unix/af_unix.c       |    8 ++++----
 8 files changed, 26 insertions(+), 23 deletions(-)

--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -1204,8 +1204,8 @@ void sk_psock_start_strp(struct sock *sk
 		return;
 
 	psock->saved_data_ready = sk->sk_data_ready;
-	sk->sk_data_ready = sk_psock_strp_data_ready;
-	sk->sk_write_space = sk_psock_write_space;
+	WRITE_ONCE(sk->sk_data_ready, sk_psock_strp_data_ready);
+	WRITE_ONCE(sk->sk_write_space, sk_psock_write_space);
 }
 
 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
@@ -1215,8 +1215,8 @@ void sk_psock_stop_strp(struct sock *sk,
 	if (!psock->saved_data_ready)
 		return;
 
-	sk->sk_data_ready = psock->saved_data_ready;
-	psock->saved_data_ready = NULL;
+	WRITE_ONCE(sk->sk_data_ready, psock->saved_data_ready);
+	WRITE_ONCE(psock->saved_data_ready, NULL);
 	strp_stop(&psock->strp);
 }
 
@@ -1298,8 +1298,8 @@ void sk_psock_start_verdict(struct sock
 		return;
 
 	psock->saved_data_ready = sk->sk_data_ready;
-	sk->sk_data_ready = sk_psock_verdict_data_ready;
-	sk->sk_write_space = sk_psock_write_space;
+	WRITE_ONCE(sk->sk_data_ready, sk_psock_verdict_data_ready);
+	WRITE_ONCE(sk->sk_write_space, sk_psock_write_space);
 }
 
 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
@@ -1310,6 +1310,6 @@ void sk_psock_stop_verdict(struct sock *
 	if (!psock->saved_data_ready)
 		return;
 
-	sk->sk_data_ready = psock->saved_data_ready;
+	WRITE_ONCE(sk->sk_data_ready, psock->saved_data_ready);
 	psock->saved_data_ready = NULL;
 }
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1346,7 +1346,7 @@ out_err:
 	err = sk_stream_error(sk, flags, err);
 	/* make sure we wake any epoll edge trigger waiter */
 	if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) {
-		sk->sk_write_space(sk);
+		READ_ONCE(sk->sk_write_space)(sk);
 		tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
 	}
 	return err;
@@ -4023,7 +4023,7 @@ ao_parse:
 		break;
 	case TCP_NOTSENT_LOWAT:
 		WRITE_ONCE(tp->notsent_lowat, val);
-		sk->sk_write_space(sk);
+		READ_ONCE(sk->sk_write_space)(sk);
 		break;
 	case TCP_INQ:
 		if (val > 1 || val < 0)
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -725,7 +725,7 @@ int tcp_bpf_update_proto(struct sock *sk
 			WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash);
 			tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 		} else {
-			sk->sk_write_space = psock->saved_write_space;
+			WRITE_ONCE(sk->sk_write_space, psock->saved_write_space);
 			/* Pairs with lockless read in sk_clone_lock() */
 			sock_replace_proto(sk, psock->sk_proto);
 		}
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5034,7 +5034,7 @@ static void tcp_data_queue_ofo(struct so
 
 	if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
-		sk->sk_data_ready(sk);
+		READ_ONCE(sk->sk_data_ready)(sk);
 		tcp_drop_reason(sk, skb, SKB_DROP_REASON_PROTO_MEM);
 		return;
 	}
@@ -5241,7 +5241,7 @@ err:
 void tcp_data_ready(struct sock *sk)
 {
 	if (tcp_epollin_ready(sk, sk->sk_rcvlowat) || sock_flag(sk, SOCK_DONE))
-		sk->sk_data_ready(sk);
+		READ_ONCE(sk->sk_data_ready)(sk);
 }
 
 static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
@@ -5297,7 +5297,7 @@ queue_and_out:
 			inet_csk(sk)->icsk_ack.pending |=
 					(ICSK_ACK_NOMEM | ICSK_ACK_NOW);
 			inet_csk_schedule_ack(sk);
-			sk->sk_data_ready(sk);
+			READ_ONCE(sk->sk_data_ready)(sk);
 
 			if (skb_queue_len(&sk->sk_receive_queue) && skb->len) {
 				reason = SKB_DROP_REASON_PROTO_MEM;
@@ -5735,7 +5735,9 @@ static void tcp_new_space(struct sock *s
 		tp->snd_cwnd_stamp = tcp_jiffies32;
 	}
 
-	INDIRECT_CALL_1(sk->sk_write_space, sk_stream_write_space, sk);
+	INDIRECT_CALL_1(READ_ONCE(sk->sk_write_space),
+			sk_stream_write_space,
+			sk);
 }
 
 /* Caller made space either from:
@@ -5941,7 +5943,7 @@ static void tcp_urg(struct sock *sk, str
 				BUG();
 			WRITE_ONCE(tp->urg_data, TCP_URG_VALID | tmp);
 			if (!sock_flag(sk, SOCK_DEAD))
-				sk->sk_data_ready(sk);
+				READ_ONCE(sk->sk_data_ready)(sk);
 		}
 	}
 }
@@ -7341,7 +7343,7 @@ int tcp_conn_request(struct request_sock
 			sock_put(fastopen_sk);
 			goto drop_and_free;
 		}
-		sk->sk_data_ready(sk);
+		READ_ONCE(sk->sk_data_ready)(sk);
 		bh_unlock_sock(fastopen_sk);
 		sock_put(fastopen_sk);
 	} else {
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -928,7 +928,7 @@ enum skb_drop_reason tcp_child_process(s
 		reason = tcp_rcv_state_process(child, skb);
 		/* Wakeup parent, send SIGIO */
 		if (state == TCP_SYN_RECV && child->sk_state != state)
-			parent->sk_data_ready(parent);
+			READ_ONCE(parent->sk_data_ready)(parent);
 	} else {
 		/* Alas, it is possible again, because we do lookup
 		 * in main socket hash table and lock on listening
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1622,7 +1622,8 @@ int __udp_enqueue_schedule_skb(struct so
 	spin_unlock(&list->lock);
 
 	if (!sock_flag(sk, SOCK_DEAD))
-		INDIRECT_CALL_1(sk->sk_data_ready, sock_def_readable, sk);
+		INDIRECT_CALL_1(READ_ONCE(sk->sk_data_ready),
+				sock_def_readable, sk);
 
 	busylock_release(busy);
 	return 0;
--- a/net/ipv4/udp_bpf.c
+++ b/net/ipv4/udp_bpf.c
@@ -158,7 +158,7 @@ int udp_bpf_update_proto(struct sock *sk
 	int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
 
 	if (restore) {
-		sk->sk_write_space = psock->saved_write_space;
+		WRITE_ONCE(sk->sk_write_space, psock->saved_write_space);
 		sock_replace_proto(sk, psock->sk_proto);
 		return 0;
 	}
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1707,7 +1707,7 @@ restart:
 	__skb_queue_tail(&other->sk_receive_queue, skb);
 	spin_unlock(&other->sk_receive_queue.lock);
 	unix_state_unlock(other);
-	other->sk_data_ready(other);
+	READ_ONCE(other->sk_data_ready)(other);
 	sock_put(other);
 	return 0;
 
@@ -2175,7 +2175,7 @@ restart_locked:
 	scm_stat_add(other, skb);
 	skb_queue_tail(&other->sk_receive_queue, skb);
 	unix_state_unlock(other);
-	other->sk_data_ready(other);
+	READ_ONCE(other->sk_data_ready)(other);
 	sock_put(other);
 	scm_destroy(&scm);
 	return len;
@@ -2243,7 +2243,7 @@ static int queue_oob(struct socket *sock
 
 	sk_send_sigurg(other);
 	unix_state_unlock(other);
-	other->sk_data_ready(other);
+	READ_ONCE(other->sk_data_ready)(other);
 
 	return err;
 }
@@ -2354,7 +2354,7 @@ static int unix_stream_sendmsg(struct so
 		scm_stat_add(other, skb);
 		skb_queue_tail(&other->sk_receive_queue, skb);
 		unix_state_unlock(other);
-		other->sk_data_ready(other);
+		READ_ONCE(other->sk_data_ready)(other);
 		sent += size;
 	}