Messages in this thread | | | From | Dexuan Cui <> | Subject | RE: [Patch v2 1/2] PCI: hv: Fix a race condition when removing the device | Date | Fri, 23 Apr 2021 07:09:54 +0000 |
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> From: longli@linuxonhyperv.com <longli@linuxonhyperv.com> > Sent: Wednesday, April 21, 2021 10:46 PM > ... > diff --git a/drivers/pci/controller/pci-hyperv.c > b/drivers/pci/controller/pci-hyperv.c > index 27a17a1e4a7c..fc948a2ed703 100644 > --- a/drivers/pci/controller/pci-hyperv.c > +++ b/drivers/pci/controller/pci-hyperv.c > @@ -444,7 +444,6 @@ enum hv_pcibus_state { > hv_pcibus_probed, > hv_pcibus_installed, > hv_pcibus_removing, > - hv_pcibus_removed, > hv_pcibus_maximum > }; > > @@ -3305,13 +3304,22 @@ static int hv_pci_remove(struct hv_device *hdev) > > hbus = hv_get_drvdata(hdev); > if (hbus->state == hv_pcibus_installed) { > + tasklet_disable(&hdev->channel->callback_event); > + hbus->state = hv_pcibus_removing; > + tasklet_enable(&hdev->channel->callback_event); > + destroy_workqueue(hbus->wq);
If we test "rmmod pci-hyperv", I suspect the warning will be printed: hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_start_relations_work():
if (hbus->state == hv_pcibus_removing) { dev_info(&hbus->hdev->device, "PCI VMBus BUS_RELATIONS: ignored\n"); return -ENOENT; }
Ideally we'd like to avoid the warning in the driver unloading case.
BTW, can you please add "hbus->wq = NULL;" after the line "destroy_workqueue(hbus->wq);"? In case some other function could still try to use hbus->wq by accident in the future, the error would be easier to be understood.
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