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8a4c5c329d
If pci_stop_and_remove_bus_device() is run concurrently for a device and its parent bridge via remove_callback(), both code paths attempt to acquire pci_rescan_remove_lock. If the child device removal acquires it first, there will be no problems. However, if the parent bridge removal acquires it first, it will eventually execute pci_destroy_dev() for the child device, but that device object will not be freed yet due to the reference held by the concurrent child removal. Consequently, both pci_stop_bus_device() and pci_remove_bus_device() will be executed for that device unnecessarily and pci_destroy_dev() will see a corrupted list head in that object. Moreover, an excess put_device() will be executed for that device in that case which may lead to a use-after-free in the final kobject_put() done by sysfs_schedule_callback_work(). To avoid that problem, make pci_destroy_dev() check if the device's parent kobject is NULL, which only happens after device_del() has already run for it. Make pci_destroy_dev() return immediately whithout doing anything in that case. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
144 lines
3.2 KiB
C
144 lines
3.2 KiB
C
#include <linux/pci.h>
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#include <linux/module.h>
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#include <linux/pci-aspm.h>
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#include "pci.h"
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static void pci_stop_dev(struct pci_dev *dev)
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{
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pci_pme_active(dev, false);
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if (dev->is_added) {
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pci_proc_detach_device(dev);
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pci_remove_sysfs_dev_files(dev);
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device_release_driver(&dev->dev);
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dev->is_added = 0;
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}
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if (dev->bus->self)
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pcie_aspm_exit_link_state(dev);
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}
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static void pci_destroy_dev(struct pci_dev *dev)
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{
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if (!dev->dev.kobj.parent)
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return;
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device_del(&dev->dev);
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put_device(&dev->dev);
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}
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void pci_remove_bus(struct pci_bus *bus)
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{
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pci_proc_detach_bus(bus);
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down_write(&pci_bus_sem);
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list_del(&bus->node);
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pci_bus_release_busn_res(bus);
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up_write(&pci_bus_sem);
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pci_remove_legacy_files(bus);
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pcibios_remove_bus(bus);
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device_unregister(&bus->dev);
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}
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EXPORT_SYMBOL(pci_remove_bus);
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static void pci_stop_bus_device(struct pci_dev *dev)
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{
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struct pci_bus *bus = dev->subordinate;
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struct pci_dev *child, *tmp;
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/*
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* Stopping an SR-IOV PF device removes all the associated VFs,
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* which will update the bus->devices list and confuse the
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* iterator. Therefore, iterate in reverse so we remove the VFs
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* first, then the PF.
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*/
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if (bus) {
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list_for_each_entry_safe_reverse(child, tmp,
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&bus->devices, bus_list)
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pci_stop_bus_device(child);
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}
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pci_stop_dev(dev);
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}
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static void pci_remove_bus_device(struct pci_dev *dev)
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{
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struct pci_bus *bus = dev->subordinate;
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struct pci_dev *child, *tmp;
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if (bus) {
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list_for_each_entry_safe(child, tmp,
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&bus->devices, bus_list)
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pci_remove_bus_device(child);
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pci_remove_bus(bus);
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dev->subordinate = NULL;
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}
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pci_destroy_dev(dev);
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}
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/**
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* pci_stop_and_remove_bus_device - remove a PCI device and any children
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* @dev: the device to remove
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*
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* Remove a PCI device from the device lists, informing the drivers
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* that the device has been removed. We also remove any subordinate
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* buses and children in a depth-first manner.
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*
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* For each device we remove, delete the device structure from the
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* device lists, remove the /proc entry, and notify userspace
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* (/sbin/hotplug).
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*/
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void pci_stop_and_remove_bus_device(struct pci_dev *dev)
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{
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pci_stop_bus_device(dev);
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pci_remove_bus_device(dev);
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}
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EXPORT_SYMBOL(pci_stop_and_remove_bus_device);
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void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev)
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{
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pci_lock_rescan_remove();
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pci_stop_and_remove_bus_device(dev);
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pci_unlock_rescan_remove();
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}
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EXPORT_SYMBOL_GPL(pci_stop_and_remove_bus_device_locked);
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void pci_stop_root_bus(struct pci_bus *bus)
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{
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struct pci_dev *child, *tmp;
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struct pci_host_bridge *host_bridge;
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if (!pci_is_root_bus(bus))
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return;
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host_bridge = to_pci_host_bridge(bus->bridge);
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list_for_each_entry_safe_reverse(child, tmp,
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&bus->devices, bus_list)
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pci_stop_bus_device(child);
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/* stop the host bridge */
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device_release_driver(&host_bridge->dev);
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}
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void pci_remove_root_bus(struct pci_bus *bus)
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{
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struct pci_dev *child, *tmp;
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struct pci_host_bridge *host_bridge;
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if (!pci_is_root_bus(bus))
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return;
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host_bridge = to_pci_host_bridge(bus->bridge);
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list_for_each_entry_safe(child, tmp,
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&bus->devices, bus_list)
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pci_remove_bus_device(child);
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pci_remove_bus(bus);
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host_bridge->bus = NULL;
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/* remove the host bridge */
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device_unregister(&host_bridge->dev);
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}
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