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

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation