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Sat, 3 Mar 2018 00:20:47 +0000 Received: from KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM ([10.170.167.17]) by KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM ([10.170.167.17]) with mapi id 15.20.0567.002; Sat, 3 Mar 2018 00:20:47 +0000 From: Dexuan Cui To: "bhelgaas@google.com" , "linux-pci@vger.kernel.org" , KY Srinivasan , Stephen Hemminger CC: "linux-kernel@vger.kernel.org" , "driverdev-devel@linuxdriverproject.org" , Haiyang Zhang , "olaf@aepfle.de" , "apw@canonical.com" , "jasowang@redhat.com" , "vkuznets@redhat.com" , "marcelo.cerri@canonical.com" , Dexuan Cui , Jack Morgenstein , "stable@vger.kernel.org" Subject: [PATCH 2/3] PCI: hv: serialize the present/eject work items Thread-Topic: [PATCH 2/3] PCI: hv: serialize the present/eject work items Thread-Index: AQHTsoV58ygEHWMoYEeyKVqO+bn/hg== Date: Sat, 3 Mar 2018 00:20:46 +0000 Message-ID: <20180303001947.20564-2-decui@microsoft.com> References: <20180303001947.20564-1-decui@microsoft.com> In-Reply-To: <20180303001947.20564-1-decui@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: git-send-email 2.15.1 authentication-results: spf=none (sender IP is ) smtp.mailfrom=decui@microsoft.com; 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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 Tested-by: Adrian Suhov Tested-by: Chris Valean Cc: Vitaly Kuznetsov Cc: Jack Morgenstein Cc: stable@vger.kernel.org Cc: Stephen Hemminger Cc: K. Y. Srinivasan --- drivers/pci/host/pci-hyperv.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 1233300f41c6..57b1fb3ebdb9 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); } /** @@ -1848,7 +1850,7 @@ 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); } /** @@ -2463,11 +2465,17 @@ 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); @@ -2536,6 +2544,9 @@ static int hv_pci_probe(struct hv_device *hdev, hv_free_config_window(hbus); close: vmbus_close(hdev->channel); +destroy_wq: + drain_workqueue(hbus->wq); + destroy_workqueue(hbus->wq); free_bus: free_page((unsigned long)hbus); return ret; @@ -2615,6 +2626,8 @@ 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); + drain_workqueue(hbus->wq); + destroy_workqueue(hbus->wq); free_page((unsigned long)hbus); return 0; }