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Commit ee72b9fd authored by David Howells's avatar David Howells
Browse files

rxrpc: Use ACCESS_ONCE() when accessing circular buffer pointers 



Use ACCESS_ONCE() when accessing the other-end pointer into a circular
buffer as it's possible the other-end pointer might change whilst we're
doing this, and if we access it twice, we might get some weird things
happening.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent b4f1342f

net/rxrpc/ar-output.c

+7 −4
Original line number Diff line number Diff line
@@ -401,7 +401,8 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx, 
	int ret;



	_enter(",{%d},%ld",

	       CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),

	       CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),

			  call->acks_winsz),

	       *timeo);



	add_wait_queue(&call->tx_waitq, &myself);
@@ -409,7 +410,7 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx, 
	for (;;) {

		set_current_state(TASK_INTERRUPTIBLE);

		ret = 0;

		if (CIRC_SPACE(call->acks_head, call->acks_tail,

		if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),

			       call->acks_winsz) > 0)

			break;

		if (signal_pending(current)) {
@@ -570,7 +571,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx, 


			_debug("alloc");



			if (CIRC_SPACE(call->acks_head, call->acks_tail,

			if (CIRC_SPACE(call->acks_head,

				       ACCESS_ONCE(call->acks_tail),

				       call->acks_winsz) <= 0) {

				ret = -EAGAIN;

				if (msg->msg_flags & MSG_DONTWAIT)
@@ -686,7 +688,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx, 
			sp->hdr.flags = conn->out_clientflag;

			if (msg_data_left(msg) == 0 && !more)

				sp->hdr.flags |= RXRPC_LAST_PACKET;

			else if (CIRC_SPACE(call->acks_head, call->acks_tail,

			else if (CIRC_SPACE(call->acks_head,

					    ACCESS_ONCE(call->acks_tail),

					    call->acks_winsz) > 1)

				sp->hdr.flags |= RXRPC_MORE_PACKETS;

			if (more && seq & 1)