From: Long Li longli@microsoft.com
[ 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 decui@microsoft.com for pointing out the race condition in create_root_hv_pci_bus().
Reported-by: Xiaofeng Wang xiaofwan@redhat.com Signed-off-by: Long Li longli@microsoft.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Acked-by: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Sasha Levin alexander.levin@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 43aa630f419a..d392a55ec0a9 100644 --- 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 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; } @@ -1597,8 +1599,10 @@ 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));