From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753223AbdKWQ30 (ORCPT <rfc822;w@1wt.eu>);
        Thu, 23 Nov 2017 11:29:26 -0500
Received: from shards.monkeyblade.net ([184.105.139.130]:44224 "EHLO
        shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1752768AbdKWQ3Y (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 23 Nov 2017 11:29:24 -0500
Date: Fri, 24 Nov 2017 01:29:23 +0900 (KST)
Message-Id: <20171124.012923.129711433515883419.davem@davemloft.net>
To: jhansen@vmware.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, gregkh@linuxfoundation.org,
        pv-drivers@vmware.com
Subject: Re: [PATCH] VSOCK: Don't call vsock_stream_has_data in atomic
 context
From: David Miller <davem@davemloft.net>
In-Reply-To: <1511261184-45913-1-git-send-email-jhansen@vmware.com>
References: <y>
        <1511261184-45913-1-git-send-email-jhansen@vmware.com>
X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 23 Nov 2017 08:29:24 -0800 (PST)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Jorgen Hansen <jhansen@vmware.com>
Date: Tue, 21 Nov 2017 02:46:24 -0800

> When using the host personality, VMCI will grab a mutex for any
> queue pair access. In the detach callback for the vmci vsock
> transport, we call vsock_stream_has_data while holding a spinlock,
> and vsock_stream_has_data will access a queue pair.
> 
> To avoid this, we can simply omit calling vsock_stream_has_data
> for host side queue pairs, since the QPs are empty per default
> when the guest has detached.
> 
> This bug affects users of VMware Workstation using kernel version
> 4.4 and later.
> 
> Testing: Ran vsock tests between guest and host, and verified that
> with this change, the host isn't calling vsock_stream_has_data
> during detach. Ran mixedTest between guest and host using both
> guest and host as server.
> 
> Reviewed-by: Adit Ranadive <aditr@vmware.com>
> Reviewed-by: Aditya Sarwade <asarwade@vmware.com>
> Signed-off-by: Jorgen Hansen <jhansen@vmware.com>

This doesn't apply cleanly to the current 'net' GIT tree.