[PATCH] PCI: fix release_pcibus_dev() crash

During the course of a hotplug removal of a PCI bus, release_pcibus_dev()
attempts to remove attribute files from a kobject directory that no longer
exists.  This patch moves these calls to pci_remove_bus(), where they can work
as intended.
Signed-off-by: John Rose <johnrose@austin.ibm.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/pci/pci.h

@@ -59,12 +59,14 @@ struct pci_visit {
 extern int pci_visit_dev(struct pci_visit *fn,
 			 struct pci_dev_wrapped *wrapped_dev,
 			 struct pci_bus_wrapped *wrapped_parent);
+extern void pci_remove_legacy_files(struct pci_bus *bus);
 
 /* Lock for read/write access to pci device and bus lists */
 extern spinlock_t pci_bus_lock;
 
 extern int pcie_mch_quirk;
 extern struct device_attribute pci_dev_attrs[];
+extern struct class_device_attribute class_device_attr_cpuaffinity;
 
 /**
  * pci_match_one_device - Tell if a PCI device structure has a matching

drivers/pci/probe.c

@@ -62,7 +62,7 @@ static void pci_create_legacy_files(struct pci_bus *b)
 	}
 }
 
-static void pci_remove_legacy_files(struct pci_bus *b)
+void pci_remove_legacy_files(struct pci_bus *b)
 {
 	class_device_remove_bin_file(&b->class_dev, b->legacy_io);
 	class_device_remove_bin_file(&b->class_dev, b->legacy_mem);
@@ -70,7 +70,7 @@ static void pci_remove_legacy_files(struct pci_bus *b)
 }
 #else /* !HAVE_PCI_LEGACY */
 static inline void pci_create_legacy_files(struct pci_bus *bus) { return; }
-static inline void pci_remove_legacy_files(struct pci_bus *bus) { return; }
+void pci_remove_legacy_files(struct pci_bus *bus) { return; }
 #endif /* HAVE_PCI_LEGACY */
 
 /*
@@ -86,7 +86,7 @@ static ssize_t pci_bus_show_cpuaffinity(struct class_device *class_dev, char *bu
 		buf[ret++] = '\n';
 	return ret;
 }
-static CLASS_DEVICE_ATTR(cpuaffinity, S_IRUGO, pci_bus_show_cpuaffinity, NULL);
+CLASS_DEVICE_ATTR(cpuaffinity, S_IRUGO, pci_bus_show_cpuaffinity, NULL);
 
 /*
  * PCI Bus Class
@@ -95,10 +95,6 @@ static void release_pcibus_dev(struct class_device *class_dev)
 {
 	struct pci_bus *pci_bus = to_pci_bus(class_dev);
 
-	pci_remove_legacy_files(pci_bus);
-	class_device_remove_file(&pci_bus->class_dev,
-				 &class_device_attr_cpuaffinity);
-	sysfs_remove_link(&pci_bus->class_dev.kobj, "bridge");
 	if (pci_bus->bridge)
 		put_device(pci_bus->bridge);
 	kfree(pci_bus);

drivers/pci/remove.c

@@ -61,15 +61,18 @@ int pci_remove_device_safe(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_remove_device_safe);
 
-void pci_remove_bus(struct pci_bus *b)
+void pci_remove_bus(struct pci_bus *pci_bus)
 {
-	pci_proc_detach_bus(b);
+	pci_proc_detach_bus(pci_bus);
 
 	spin_lock(&pci_bus_lock);
-	list_del(&b->node);
+	list_del(&pci_bus->node);
 	spin_unlock(&pci_bus_lock);
-
-	class_device_unregister(&b->class_dev);
+	pci_remove_legacy_files(pci_bus);
+	class_device_remove_file(&pci_bus->class_dev,
+		&class_device_attr_cpuaffinity);
+	sysfs_remove_link(&pci_bus->class_dev.kobj, "bridge");
+	class_device_unregister(&pci_bus->class_dev);
 }
 EXPORT_SYMBOL(pci_remove_bus);