Re: [PATCH] iommu: Fix group refcount in iommu_alloc_default_domain()

[Sai Prakash Ranjan]

Hi Joerg,

On 2020-05-25 18:32, Joerg Roedel wrote:
Hi,
On Fri, May 22, 2020 at 06:31:45PM +0530, Sai Prakash Ranjan wrote:
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index a4c2f122eb8b..05f7b77c432f 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1491,6 +1491,7 @@ static int iommu_alloc_default_domain(struct 
device *dev)
 {
        struct iommu_group *group;
        unsigned int type;
+       int ret;

        group = iommu_group_get(dev);
        if (!group)
@@ -1501,7 +1502,11 @@ static int iommu_alloc_default_domain(struct 
device *dev)

        type = iommu_get_def_domain_type(dev);

-       return iommu_group_alloc_default_domain(dev->bus, group, type);
+       ret = iommu_group_alloc_default_domain(dev->bus, group, type);
+
+       iommu_group_put(group);
+
+       return ret;
 }

 /**

Thanks for the report and the fix. I think it is better to fix this by
not taking a group reference in iommu_alloc_default_domain() at all and
pass group as a parameter. Please see the patch I just sent out.


Thanks for the patch, it looks like the right thing to do. Testing it
out now.

Thanks,
Sai

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