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 potentailly modify the bus from multiple places. Properly lock the bus access.
Thanks Dexuan Cui <de...@microsoft.com> for pointing out the race condition in create_root_hv_pci_bus(). Signed-off-by: Long Li <lon...@microsoft.com> Reported-by: Xiaofeng Wang <xiaof...@redhat.com> Acked-by: K. Y. Srinivasan <k...@microsoft.com> --- 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 4a37598..33c75c9 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1198,9 +1198,11 @@ 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; } @@ -1590,8 +1592,10 @@ 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(); } memset(&ctxt, 0, sizeof(ctxt)); -- 1.8.5.6