Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754126Ab3FJQ6t (ORCPT ); Mon, 10 Jun 2013 12:58:49 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:19068 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752539Ab3FJQ6r (ORCPT ); Mon, 10 Jun 2013 12:58:47 -0400 Date: Mon, 10 Jun 2013 12:58:01 -0400 From: Konrad Rzeszutek Wilk To: Jiang Liu Cc: Bjorn Helgaas , Yinghai Lu , Jiang Liu , "Rafael J . Wysocki" , Greg Kroah-Hartman , Gu Zheng , Toshi Kani , Myron Stowe , Yijing Wang , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Jeremy Fitzhardinge , xen-devel@lists.xensource.com, virtualization@lists.linux-foundation.org Subject: Re: [RFC PATCH v2, part3 07/11] PCI, xen-pcifront: use new PCI interfaces to simplify implementation Message-ID: <20130610165801.GA24823@phenom.dumpdata.com> References: <1368719459-24800-1-git-send-email-jiang.liu@huawei.com> <1368719459-24800-8-git-send-email-jiang.liu@huawei.com> <20130607145024.GA16631@phenom.dumpdata.com> <20130607153822.GA24882@phenom.dumpdata.com> <51B20F57.7050100@gmail.com> <20130607170706.GB3730@phenom.dumpdata.com> <51B4B266.5010100@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51B4B266.5010100@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2890 Lines: 66 On Mon, Jun 10, 2013 at 12:50:46AM +0800, Jiang Liu wrote: > On Sat 08 Jun 2013 01:07:06 AM CST, Konrad Rzeszutek Wilk wrote: > > On Sat, Jun 08, 2013 at 12:50:31AM +0800, Jiang Liu wrote: > >> On 06/07/2013 11:38 PM, Konrad Rzeszutek Wilk wrote: > >>> On Fri, Jun 07, 2013 at 10:50:24AM -0400, Konrad Rzeszutek Wilk wrote: > >>>> On Thu, May 16, 2013 at 11:50:55PM +0800, Jiang Liu wrote: > >>>>> Use new PCI interfaces to simplify xen-pcifront implementation: > >>>>> 1) Use pci_create_root_bus() instead of pci_scan_bus_parented() > >>>>> because pci_scan_bus_parented() is marked as __deprecated.This > >>>>> also gets rid of a duplicated call of pci_bus_start_devices(). > >>>>> 2) Use pci_stop_root_bus() and pci_remove_root_bus() instead of > >>>>> open-coded private implementation. > >>>>> 3) Use pci_set_host_bridge_release() to release data structures > >>>>> associated with PCI root buses. > >>>>> 4) Use pci_bus_get()/pci_bus_put() to manage PCI root bus reference > >>>>> count. > >>>>> > >>>>> This is also a preparation for coming PCI bus lock enhancement. > >>> > >>> With this patch from : > >>> > >>> Merge branch 'pci_lock_v3' of https://github.com/jiangliu/linux into testing > >>> > >>> > >>> it blows up when detaching the device. > >> Hi Konrad, > >> Thanks for testing! According to the log messages, this issue should > >> be related to pci bus reference counter management. Seems we have done > >> an extra(unbalanced) release of pci bus device. > >> Will investigate it tomorrow! > > > > That is quite commendable that you are willing to look over this on > > the weekend but I am not going to be able to rerun this test until > > some time in the week. You could enjoy the weekend and just look at > > this during the week. > > Hi Konrad, > We should have root-caused this bug, which is caused by > for_each_pci_root_bus(). > Current implementation doesn't support root bus deletion when walking > PCI root > buses by for_each_pci_root_bus(). The reference counter > (pci_bus->dev.knode_class.n_ref) > becomes zero after returning from pci_remove_root_bus(), so it triggers > kref warnings > and double-free of klist_node object when we call > pci_get_next_root_bus() to get the > next PCI root bus. > So we will first revert to list_for_each_entry_safe(bus, temp, > &pci_root_buses, node) > and solve this issue in next version of for_each_pci_root_bus(). That definitly solves the issue. Thanks! I used pci_lock_v3 of https://github.com/jiangliu/linux and the fix below. Is there a new patchset you are going to be posting or a git branch that I can look over? Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/