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 S1750896AbdAaHAv (ORCPT <rfc822;w@1wt.eu>);
        Tue, 31 Jan 2017 02:00:51 -0500
Received: from mail.linuxfoundation.org ([140.211.169.12]:34474 "EHLO
        mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1750740AbdAaHAs (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 31 Jan 2017 02:00:48 -0500
Date: Tue, 31 Jan 2017 08:00:51 +0100
From: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To: Ajay Kaher <ajay.kaher@samsung.com>
Cc: "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        AMAN DEEP <aman.deep@samsung.com>,
        HEMANSHU SRIVASTAVA <hemanshu.s@samsung.com>
Subject: Re: Re: Subject: [PATCH v1] USB:Core: BugFix: Proper handling of
 Race Condition when two USB class drivers try to call init_usb_class
 simultaneously
Message-ID: <20170131070051.GA5149@kroah.com>
References: <CGME20170130082525epcms5p5e2459e715ebb80cef1574946e3f6ffbf@epcms5p5>
 <20170130082525epcms5p5e2459e715ebb80cef1574946e3f6ffbf@epcms5p5>
 <20170131052146epcms5p79112e0ba47847b8b0d33aee7b66590c9@epcms5p7>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20170131052146epcms5p79112e0ba47847b8b0d33aee7b66590c9@epcms5p7>
User-Agent: Mutt/1.7.2 (2016-11-26)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


A: http://en.wikipedia.org/wiki/Top_post
Q: Were do I find info about this thing called top-posting?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?


http://daringfireball.net/2007/07/on_top

On Tue, Jan 31, 2017 at 05:21:46AM +0000, Ajay Kaher wrote:
> 
>  
> At boot time, probe function of multiple connected devices
> (proprietary devices) execute simultaneously.

What exactly do you mean here?  How can probe happen "simultaneously"?
The USB core prevents this, right?

And what do you mean exactly by "(proprietary devices)"?

> And because of the following code path race condition happens:
> probe->usb_register_dev->init_usb_class

Why is this just showing up now, and hasn't been an issue for the decade
or so this code has been around?  What changed?

> Tested with these changes, and problem has been solved.

What changes?

thanks,

greg k-h