From 414428c5da1c71986727c2fa5cdf1ed071e398d7 Mon Sep 17 00:00:00 2001 From: Long Li Date: Thu, 23 Mar 2017 14:58:32 -0700 Subject: [PATCH] PCI: hv: Lock PCI bus on device eject 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 --- drivers/pci/host/pci-hyperv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 39fafda4deff..a1b3c1957d43 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1209,9 +1209,11 @@ static int create_root_hv_pci_bus(struct hv_pcibus_device *hbus) 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; } @@ -1612,8 +1614,10 @@ static void hv_eject_device_work(struct work_struct *work) 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(); } spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); -- 2.20.1