From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1037497AbdE0BU7 (ORCPT ); Fri, 26 May 2017 21:20:59 -0400 Received: from mail-pf0-f173.google.com ([209.85.192.173]:34062 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1948864AbdEZX6X (ORCPT ); Fri, 26 May 2017 19:58:23 -0400 Date: Fri, 26 May 2017 16:58:20 -0700 From: Jakub Kicinski To: Bjorn Helgaas Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Emil Tantilov , Alexander Duyck , oss-drivers@netronome.com Subject: Re: [PATCH] pci: iov: use device lock to protect IOV sysfs accesses Message-ID: <20170526165820.7ec488e3@cakuba.netronome.com> In-Reply-To: <20170526234726.GD21531@bhelgaas-glaptop.roam.corp.google.com> References: <20170522225023.14010-1-jakub.kicinski@netronome.com> <20170526234726.GD21531@bhelgaas-glaptop.roam.corp.google.com> Organization: Netronome Systems, Ltd. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 26 May 2017 18:47:26 -0500, Bjorn Helgaas wrote: > On Mon, May 22, 2017 at 03:50:23PM -0700, Jakub Kicinski wrote: > > PCI core sets the driver pointer before calling ->probe() and only > > clears it after ->remove(). This means driver's ->sriov_configure() > > callback will happily race with probe() and remove(), most likely > > leading to BUGs, since drivers don't expect this. > > I guess you're referring to the pci_dev->driver pointer set by > local_pci_probe(), and this is important because sriov_numvfs_store() > checks that pointer, right? Yes, exactly. I initially thought this is how the safety of sriov callback may have been ensured, but since the order of local_pci_probe() and the assignment is what it is, it can't.