From: Gavin Shan Date: Mon, 13 Jan 2014 03:36:22 +0000 (+0800) Subject: powerpc/iommu: Don't detach device without IOMMU group X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=0c4b9e27b09eeb4da84451c038a587b92ce93ff5;p=openwrt%2Fstaging%2Fblogic.git 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 --- diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index f58d8135aab2..d773dd440a45 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);