Merge branch 'rxrpc-miscellaneous-fixes'

David Howells says:

====================
rxrpc: Miscellaneous fixes

Here some miscellaneous fixes for AF_RXRPC:

 (1) Fix a race in the I/O thread vs UDP socket setup.

 (2) Fix an uninitialised variable.
====================

Link: https://patch.msgid.link/20241001132702.3122709-1-dhowells@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/rxrpc/ar-internal.h

@@ -1056,7 +1056,7 @@ bool rxrpc_direct_abort(struct sk_buff *skb, enum rxrpc_abort_reason why,
 int rxrpc_io_thread(void *data);
 static inline void rxrpc_wake_up_io_thread(struct rxrpc_local *local)
 {
-	wake_up_process(local->io_thread);
+	wake_up_process(READ_ONCE(local->io_thread));
 }
 
 static inline bool rxrpc_protocol_error(struct sk_buff *skb, enum rxrpc_abort_reason why)

net/rxrpc/io_thread.c

@@ -27,11 +27,17 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb)
 {
 	struct sk_buff_head *rx_queue;
 	struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
+	struct task_struct *io_thread;
 
 	if (unlikely(!local)) {
 		kfree_skb(skb);
 		return 0;
 	}
+	io_thread = READ_ONCE(local->io_thread);
+	if (!io_thread) {
+		kfree_skb(skb);
+		return 0;
+	}
 	if (skb->tstamp == 0)
 		skb->tstamp = ktime_get_real();
 
@@ -47,7 +53,7 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb)
 #endif
 
 	skb_queue_tail(rx_queue, skb);
-	rxrpc_wake_up_io_thread(local);
+	wake_up_process(io_thread);
 	return 0;
 }
 
@@ -565,7 +571,7 @@ int rxrpc_io_thread(void *data)
 	__set_current_state(TASK_RUNNING);
 	rxrpc_see_local(local, rxrpc_local_stop);
 	rxrpc_destroy_local(local);
-	local->io_thread = NULL;
+	WRITE_ONCE(local->io_thread, NULL);
 	rxrpc_see_local(local, rxrpc_local_stopped);
 	return 0;
 }

net/rxrpc/local_object.c

@@ -232,7 +232,7 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
 	}
 
 	wait_for_completion(&local->io_thread_ready);
-	local->io_thread = io_thread;
+	WRITE_ONCE(local->io_thread, io_thread);
 	_leave(" = 0");
 	return 0;
 

net/rxrpc/sendmsg.c

@@ -303,6 +303,11 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 reload:
+	txb = call->tx_pending;
+	call->tx_pending = NULL;
+	if (txb)
+		rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
+
 	ret = -EPIPE;
 	if (sk->sk_shutdown & SEND_SHUTDOWN)
 		goto maybe_error;
@@ -329,11 +334,6 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 			goto maybe_error;
 	}
 
-	txb = call->tx_pending;
-	call->tx_pending = NULL;
-	if (txb)
-		rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
-
 	do {
 		if (!txb) {
 			size_t remain;