iommu: Don't call .probe_finalize() under group->mutex (70b8170e) · Commits · 戴 / test

The .probe_finalize() call-back of some IOMMU drivers calls into arm_iommu_attach_device(). This function will call back into the IOMMU core code, where it tries to take group->mutex again, resulting in a deadlock. As there is no reason why .probe_finalize() needs to be called under that mutex, move it after the lock has been released to fix the deadlock. Fixes: ("iommu: Split off default domain allocation from group assignment") Reported-by:

Yong Wu <yong.wu@mediatek.com> Tested-by:

Yong Wu <yong.wu@mediatek.com> Signed-off-by:

Joerg Roedel <jroedel@suse.de> Cc: Yong Wu <yong.wu@mediatek.com> Link: https://lore.kernel.org/r/20200519132824.15163-1-joro@8bytes.org

drivers/iommu/iommu.c

+18 −10

Original line number	Diff line number	Diff line
		@@ -1674,17 +1674,8 @@ static void probe_alloc_default_domain(struct bus_type *bus,
		static int iommu_group_do_dma_attach(struct device dev, void data)
		{
		struct iommu_domain *domain = data;
		const struct iommu_ops *ops;
		int ret;

		ret = __iommu_attach_device(domain, dev);

		ops = domain->ops;

		if (ret == 0 && ops->probe_finalize)
		ops->probe_finalize(dev);

		return ret;
		return __iommu_attach_device(domain, dev);
		}

		static int __iommu_group_dma_attach(struct iommu_group *group)
		@@ -1693,6 +1684,21 @@ static int __iommu_group_dma_attach(struct iommu_group *group)
		iommu_group_do_dma_attach);
		}

		static int iommu_group_do_probe_finalize(struct device dev, void data)
		{
		struct iommu_domain *domain = data;

		if (domain->ops->probe_finalize)
		domain->ops->probe_finalize(dev);

		return 0;
		}

		static void __iommu_group_dma_finalize(struct iommu_group *group)
		{
		__iommu_group_for_each_dev(group, group->default_domain,
		iommu_group_do_probe_finalize);
		}
		static int iommu_do_create_direct_mappings(struct device dev, void data)
		{
		struct iommu_group *group = data;
		@@ -1745,6 +1751,8 @@ int bus_iommu_probe(struct bus_type *bus)

		if (ret)
		break;

		__iommu_group_dma_finalize(group);
		}

		return ret;

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