iommu: Don't take group reference in iommu_alloc_default_domain() (79659190) · Commits · 戴 / test

The iommu_alloc_default_domain() function takes a reference to an IOMMU group without releasing it. This causes the group to never be released, with undefined side effects. The function has only one call-site, which takes a group reference on its own, so to fix this leak, do not take another reference in iommu_alloc_default_domain() and pass the group as a function parameter instead. Fixes: ("iommu: Move default domain allocation to iommu_probe_device()") Reported-by:

Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Signed-off-by:

Joerg Roedel <jroedel@suse.de> Tested-by:

Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Link: https://lore.kernel.org/r/20200525130122.380-1-joro@8bytes.org Reference: https://lore.kernel.org/lkml/20200522130145.30067-1-saiprakash.ranjan@codeaurora.org/

drivers/iommu/iommu.c

+9 −12

Original line number	Diff line number	Diff line
		@@ -80,7 +80,8 @@ static bool iommu_cmd_line_dma_api(void)
		return !!(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API);
		}

		static int iommu_alloc_default_domain(struct device *dev);
		static int iommu_alloc_default_domain(struct iommu_group *group,
		struct device *dev);
		static struct iommu_domain __iommu_domain_alloc(struct bus_type bus,
		unsigned type);
		static int __iommu_attach_device(struct iommu_domain *domain,
		@@ -251,17 +252,17 @@ int iommu_probe_device(struct device *dev)
		if (ret)
		goto err_out;

		group = iommu_group_get(dev);
		if (!group)
		goto err_release;

		/*
		* Try to allocate a default domain - needs support from the
		* IOMMU driver. There are still some drivers which don't
		* support default domains, so the return value is not yet
		* checked.
		*/
		iommu_alloc_default_domain(dev);

		group = iommu_group_get(dev);
		if (!group)
		goto err_release;
		iommu_alloc_default_domain(group, dev);

		if (group->default_domain)
		ret = __iommu_attach_device(group->default_domain, dev);
		@@ -1478,15 +1479,11 @@ static int iommu_group_alloc_default_domain(struct bus_type *bus,
		return 0;
		}

		static int iommu_alloc_default_domain(struct device *dev)
		static int iommu_alloc_default_domain(struct iommu_group *group,
		struct device *dev)
		{
		struct iommu_group *group;
		unsigned int type;

		group = iommu_group_get(dev);
		if (!group)
		return -ENODEV;

		if (group->default_domain)
		return 0;

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