Commit 0c4b9e27 authored by Gavin Shan's avatar Gavin Shan Committed by Benjamin Herrenschmidt

powerpc/iommu: Don't detach device without IOMMU group

Some devices, for example PCI root port, don't have IOMMU table and
group. We needn't detach them from their IOMMU group. Otherwise, it
potentially incurs kernel crash because of referring NULL IOMMU group
as following backtrace indicates:

  .iommu_group_remove_device+0x74/0x1b0
  .iommu_bus_notifier+0x94/0xb4
  .notifier_call_chain+0x78/0xe8
  .__blocking_notifier_call_chain+0x7c/0xbc
  .blocking_notifier_call_chain+0x38/0x48
  .device_del+0x50/0x234
  .pci_remove_bus_device+0x88/0x138
  .pci_stop_and_remove_bus_device+0x2c/0x40
  .pcibios_remove_pci_devices+0xcc/0xfc
  .pcibios_remove_pci_devices+0x3c/0xfc
Signed-off-by: default avatarGavin Shan <shangw@linux.vnet.ibm.com>
Reviewed-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent f26c7a03
...@@ -1144,6 +1144,17 @@ EXPORT_SYMBOL_GPL(iommu_add_device); ...@@ -1144,6 +1144,17 @@ EXPORT_SYMBOL_GPL(iommu_add_device);
void iommu_del_device(struct device *dev) void iommu_del_device(struct device *dev)
{ {
/*
* Some devices might not have IOMMU table and group
* and we needn't detach them from the associated
* IOMMU groups
*/
if (!dev->iommu_group) {
pr_debug("iommu_tce: skipping device %s with no tbl\n",
dev_name(dev));
return;
}
iommu_group_remove_device(dev); iommu_group_remove_device(dev);
} }
EXPORT_SYMBOL_GPL(iommu_del_device); EXPORT_SYMBOL_GPL(iommu_del_device);
......
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