From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48612 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031272AbeCSSWi (ORCPT ); Mon, 19 Mar 2018 14:22:38 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiaofeng Wang , Long Li , Bjorn Helgaas , "K. Y. Srinivasan" , Sasha Levin Subject: [PATCH 4.9 061/241] PCI: hv: Lock PCI bus on device eject Date: Mon, 19 Mar 2018 19:05:26 +0100 Message-Id: <20180319180753.729464994@linuxfoundation.org> In-Reply-To: <20180319180751.172155436@linuxfoundation.org> References: <20180319180751.172155436@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Long Li [ Upstream commit 414428c5da1c71986727c2fa5cdf1ed071e398d7 ] A PCI_EJECT message can arrive at the same time we are calling pci_scan_child_bus() in the workqueue for the previous PCI_BUS_RELATIONS message or in create_root_hv_pci_bus(). In this case we could potentially modify the bus from multiple places. Properly lock the bus access. Thanks Dexuan Cui for pointing out the race condition in create_root_hv_pci_bus(). Reported-by: Xiaofeng Wang Signed-off-by: Long Li Signed-off-by: Bjorn Helgaas Acked-by: K. Y. Srinivasan Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/pci/host/pci-hyperv.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1206,9 +1206,11 @@ static int create_root_hv_pci_bus(struct hbus->pci_bus->msi = &hbus->msi_chip; hbus->pci_bus->msi->dev = &hbus->hdev->device; + pci_lock_rescan_remove(); pci_scan_child_bus(hbus->pci_bus); pci_bus_assign_resources(hbus->pci_bus); pci_bus_add_devices(hbus->pci_bus); + pci_unlock_rescan_remove(); hbus->state = hv_pcibus_installed; return 0; } @@ -1597,8 +1599,10 @@ static void hv_eject_device_work(struct pdev = pci_get_domain_bus_and_slot(hpdev->hbus->sysdata.domain, 0, wslot); if (pdev) { + pci_lock_rescan_remove(); pci_stop_and_remove_bus_device(pdev); pci_dev_put(pdev); + pci_unlock_rescan_remove(); } memset(&ctxt, 0, sizeof(ctxt));