From 0c4b9e27b09eeb4da84451c038a587b92ce93ff5 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Mon, 13 Jan 2014 11:36:22 +0800 Subject: [PATCH] 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: Gavin Shan Reviewed-by: Alexey Kardashevskiy Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/iommu.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index f58d813..d773dd4 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1144,6 +1144,17 @@ EXPORT_SYMBOL_GPL(iommu_add_device); 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); } EXPORT_SYMBOL_GPL(iommu_del_device); -- 2.7.4