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Commit 414428c5 authored by Long Li's avatar Long Li Committed by Bjorn Helgaas
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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 <decui@microsoft.com> for pointing out the race condition
in create_root_hv_pci_bus().

Reported-by: default avatarXiaofeng Wang <xiaofwan@redhat.com>
Signed-off-by: default avatarLong Li <longli@microsoft.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
parent d3a78d8b

drivers/pci/host/pci-hyperv.c

+4 −0
Original line number Diff line number Diff line
@@ -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);