| Message ID | 20180306182128.23281-4-decui@microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
> -----Original Message----- > From: Dexuan Cui > Sent: Tuesday, March 6, 2018 10:22 AM > To: bhelgaas@google.com; linux-pci@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; > Stephen Hemminger <sthemmin@microsoft.com>; olaf@aepfle.de; apw@canonical.com; > jasowang@redhat.com > Cc: linux-kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org; Haiyang Zhang > <haiyangz@microsoft.com>; vkuznets@redhat.com; marcelo.cerri@canonical.com; Michael > Kelley (EOSG) <Michael.H.Kelley@microsoft.com>; Dexuan Cui <decui@microsoft.com>; Jack > Morgenstein <jackm@mellanox.com>; stable@vger.kernel.org > Subject: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items > > When we hot-remove the device, we first receive a PCI_EJECT message and > then receive a PCI_BUS_RELATIONS message with bus_rel->device_count == 0. > > The first message is offloaded to hv_eject_device_work(), and the second > is offloaded to pci_devices_present_work(). Both the paths can be running > list_del(&hpdev->list_entry), causing general protection fault, because > system_wq can run them concurrently. > > The patch eliminates the race condition. > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > Tested-by: Adrian Suhov <v-adsuho@microsoft.com> > Tested-by: Chris Valean <v-chvale@microsoft.com> > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Cc: Jack Morgenstein <jackm@mellanox.com> > Cc: stable@vger.kernel.org > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Cc: K. Y. Srinivasan <kys@microsoft.com> > --- > drivers/pci/host/pci-hyperv.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> -----Original Message----- > From: Dexuan Cui > Sent: Tuesday, March 6, 2018 1:22 PM > To: bhelgaas@google.com; linux-pci@vger.kernel.org; KY Srinivasan > <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>; > olaf@aepfle.de; apw@canonical.com; jasowang@redhat.com > Cc: linux-kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org; > Haiyang Zhang <haiyangz@microsoft.com>; vkuznets@redhat.com; > marcelo.cerri@canonical.com; Michael Kelley (EOSG) > <Michael.H.Kelley@microsoft.com>; Dexuan Cui <decui@microsoft.com>; Jack > Morgenstein <jackm@mellanox.com>; stable@vger.kernel.org > Subject: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items > > When we hot-remove the device, we first receive a PCI_EJECT message and > then receive a PCI_BUS_RELATIONS message with bus_rel->device_count == 0. > > The first message is offloaded to hv_eject_device_work(), and the second is > offloaded to pci_devices_present_work(). Both the paths can be running > list_del(&hpdev->list_entry), causing general protection fault, because > system_wq can run them concurrently. > > The patch eliminates the race condition. > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > Tested-by: Adrian Suhov <v-adsuho@microsoft.com> > Tested-by: Chris Valean <v-chvale@microsoft.com> > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Cc: Jack Morgenstein <jackm@mellanox.com> > Cc: stable@vger.kernel.org > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Cc: K. Y. Srinivasan <kys@microsoft.com> > --- Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 04edb24c92ee..aaee41faf55f 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -461,6 +461,8 @@ struct hv_pcibus_device { struct retarget_msi_interrupt retarget_msi_interrupt_params; spinlock_t retarget_msi_interrupt_lock; + + struct workqueue_struct *wq; }; /* @@ -1770,7 +1772,7 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus, spin_unlock_irqrestore(&hbus->device_list_lock, flags); get_hvpcibus(hbus); - schedule_work(&dr_wrk->wrk); + queue_work(hbus->wq, &dr_wrk->wrk); } /** @@ -1845,7 +1847,7 @@ static void hv_pci_eject_device(struct hv_pci_dev *hpdev) get_pcichild(hpdev, hv_pcidev_ref_pnp); INIT_WORK(&hpdev->wrk, hv_eject_device_work); get_hvpcibus(hpdev->hbus); - schedule_work(&hpdev->wrk); + queue_work(hpdev->hbus->wq, &hpdev->wrk); } /** @@ -2460,11 +2462,17 @@ static int hv_pci_probe(struct hv_device *hdev, spin_lock_init(&hbus->retarget_msi_interrupt_lock); sema_init(&hbus->enum_sem, 1); init_completion(&hbus->remove_event); + hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0, + hbus->sysdata.domain); + if (!hbus->wq) { + ret = -ENOMEM; + goto free_bus; + } ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0, hv_pci_onchannelcallback, hbus); if (ret) - goto free_bus; + goto destroy_wq; hv_set_drvdata(hdev, hbus); @@ -2533,6 +2541,8 @@ static int hv_pci_probe(struct hv_device *hdev, hv_free_config_window(hbus); close: vmbus_close(hdev->channel); +destroy_wq: + destroy_workqueue(hbus->wq); free_bus: free_page((unsigned long)hbus); return ret; @@ -2612,6 +2622,7 @@ static int hv_pci_remove(struct hv_device *hdev) irq_domain_free_fwnode(hbus->sysdata.fwnode); put_hvpcibus(hbus); wait_for_completion(&hbus->remove_event); + destroy_workqueue(hbus->wq); free_page((unsigned long)hbus); return 0; }