4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Long Li <[email protected]> [ 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 <[email protected]> for pointing out the race condition in create_root_hv_pci_bus(). Reported-by: Xiaofeng Wang <[email protected]> Signed-off-by: Long Li <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]> Acked-by: K. Y. Srinivasan <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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));
