PCI: vmd: Detach resources after stopping root bus

Jon Derrick · Lorenzo Pieralisi · commit dc8af3a827df · 2018-10-18T17:21:14.000+01:00
The VMD removal path calls pci_stop_root_busi(), which tears down the pcie tree, including detaching all of the attached drivers. During driver detachment, devices may use pci_release_region() to release resources. This path relies on the resource being accessible in resource tree. By detaching the child domain from the parent resource domain prior to stopping the bus, we are preventing the list traversal from finding the resource to be freed. If we instead detach the resource after stopping the bus, we will have properly freed the resource and detaching is simply accounting at that point. Without this order, the resource is never freed and is orphaned on VMD removal, leading to a warning: [ 181.940162] Trying to free nonexistent resource <e5a10000-e5a13fff> Fixes: 2c2c5c5 ("x86/PCI: VMD: Attach VMD resources to parent domain's resource tree") Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> [lorenzo.pieralisi@arm.com: updated commit log] Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Keith Busch <keith.busch@intel.com>
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
@@ -813,12 +813,12 @@ static void vmd_remove(struct pci_dev *dev)
 {
 	struct vmd_dev *vmd = pci_get_drvdata(dev);
 
-	vmd_detach_resources(vmd);
 	sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
 	pci_stop_root_bus(vmd->bus);
 	pci_remove_root_bus(vmd->bus);
 	vmd_cleanup_srcu(vmd);
 	vmd_teardown_dma_ops(vmd);
+	vmd_detach_resources(vmd);
 	irq_domain_remove(vmd->irq_domain);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -813,12 +813,12 @@ static void vmd_remove(struct pci_dev *dev)`
`813`	`813`	`{`
`814`	`814`	`struct vmd_dev *vmd = pci_get_drvdata(dev);`
`815`	`815`
`816`		`- vmd_detach_resources(vmd);`
`817`	`816`	`sysfs_remove_link(&vmd->dev->dev.kobj, "domain");`
`818`	`817`	`pci_stop_root_bus(vmd->bus);`
`819`	`818`	`pci_remove_root_bus(vmd->bus);`
`820`	`819`	`vmd_cleanup_srcu(vmd);`
`821`	`820`	`vmd_teardown_dma_ops(vmd);`
	`821`	`+ vmd_detach_resources(vmd);`
`822`	`822`	`irq_domain_remove(vmd->irq_domain);`
`823`	`823`	`}`
`824`	`824`