Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934710AbdCJJXY (ORCPT ); Fri, 10 Mar 2017 04:23:24 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:37996 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934108AbdCJJXT (ORCPT ); Fri, 10 Mar 2017 04:23:19 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "K. Y. Srinivasan" Subject: [PATCH 4.9 111/153] Drivers: hv: vmbus: Prevent sending data on a rescinded channel Date: Fri, 10 Mar 2017 10:09:04 +0100 Message-Id: <20170310083953.621520236@linuxfoundation.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170310083947.108106897@linuxfoundation.org> References: <20170310083947.108106897@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1351 Lines: 45 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: K. Y. Srinivasan commit e7e97dd8b77ee7366f2f8c70a033bf5fa05ec2e0 upstream. After the channel is rescinded, the host does not read from the rescinded channel. Fail writes to a channel that has already been rescinded. If we permit writes on a rescinded channel, since the host will not respond we will have situations where we will be unable to unload vmbus drivers that cannot have any outstanding requests to the host at the point they are unoaded. Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/ring_buffer.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -298,6 +298,9 @@ int hv_ringbuffer_write(struct vmbus_cha unsigned long flags = 0; struct hv_ring_buffer_info *outring_info = &channel->outbound; + if (channel->rescind) + return -ENODEV; + for (i = 0; i < kv_count; i++) totalbytes_towrite += kv_list[i].iov_len; @@ -350,6 +353,10 @@ int hv_ringbuffer_write(struct vmbus_cha spin_unlock_irqrestore(&outring_info->ring_lock, flags); hv_signal_on_write(old_write, channel, kick_q); + + if (channel->rescind) + return -ENODEV; + return 0; }