From: Long Li <longli@microsoft.com>
To: KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Bjorn Helgaas <bhelgaas@google.com>
Cc: "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: [PATCH 2/2 v4] pci-hyperv: lock pci bus on device eject
Date: Tue, 28 Feb 2017 02:22:04 +0000 [thread overview]
Message-ID: <BN3PR03MB2227E6DE747C7C07C2B762ECCE560@BN3PR03MB2227.namprd03.prod.outlook.com> (raw)
A PCI_EJECT message can arrive at the same time we are calling=20
pci_scan_child_bus in the workqueue for the previous PCI_BUS_RELATIONS=20
message or in create_root_hv_pci_bus(), in this case we could=20
potentially modify the bus from multiple places.=20
Properly lock the bus access.
Thanks Dexuan Cui <decui@microsoft.com> for pointing out the race condition=
in create_root_hv_pci_bus().
Signed-off-by: Long Li <longli@microsoft.com>
Reported-by: Xiaofeng Wang <xiaofwan@redhat.com>
Acked-by: K. Y. Srinivasan <kys@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 4a37598..33c75c9 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -1198,9 +1198,11 @@ static int create_root_hv_pci_bus(struct hv_pcibus_d=
evice *hbus)
hbus->pci_bus->msi =3D &hbus->msi_chip;
hbus->pci_bus->msi->dev =3D &hbus->hdev->device;
=20
+ 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 =3D hv_pcibus_installed;
return 0;
}
@@ -1590,8 +1592,10 @@ static void hv_eject_device_work(struct work_struct =
*work)
pdev =3D 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();
}
=20
memset(&ctxt, 0, sizeof(ctxt));
--=20
1.8.5.6
reply other threads:[~2017-02-28 3:02 UTC|newest]
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