From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755458AbcIQXTW (ORCPT ); Sat, 17 Sep 2016 19:19:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50012 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755072AbcIQXTJ (ORCPT ); Sat, 17 Sep 2016 19:19:09 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH net-next 12/14] rxrpc: Don't transmit an ACK if there's no reason set From: David Howells To: netdev@vger.kernel.org Cc: dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Sun, 18 Sep 2016 00:19:07 +0100 Message-ID: <147415434767.17897.5111366020912850823.stgit@warthog.procyon.org.uk> In-Reply-To: <147415426459.17897.13899206413543061473.stgit@warthog.procyon.org.uk> References: <147415426459.17897.13899206413543061473.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Sat, 17 Sep 2016 23:19:09 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Don't transmit an ACK if call->ackr_reason in unset. There's the possibility of a race between recvmsg() sending an ACK and the background processing thread trying to send the same one. Signed-off-by: David Howells --- net/rxrpc/output.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index 06a9aca739d1..aa0507214b31 100644 --- a/net/rxrpc/output.c +++ b/net/rxrpc/output.c @@ -137,6 +137,11 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type) switch (type) { case RXRPC_PACKET_TYPE_ACK: spin_lock_bh(&call->lock); + if (!call->ackr_reason) { + spin_unlock_bh(&call->lock); + ret = 0; + goto out; + } n = rxrpc_fill_out_ack(call, pkt); call->ackr_reason = 0;