Re: [PATCH Trivial] intel-iommu: check return value ofdevice_to_iommu() before using it

[Joerg Roedel]

On Thu, Jan 09, 2014 at 09:58:42AM +0800, ethan zhao wrote:
>  drivers/iommu/intel-iommu.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 40203ad..5b4531a 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -1105,6 +1105,8 @@ static struct device_domain_info
> *iommu_support_dev_iotlb(
>      struct device_domain_info *info;
>      struct intel_iommu *iommu = device_to_iommu(segment, bus, devfn);
> 
> +    if (!iommu)
> +        return NULL;
>      if (!ecap_dev_iotlb_support(iommu->ecap))
>          return NULL;

This call can not fail, iommu_support_dev_iotlb() is only called from
domain_context_mapping_one() which does the iommu==NULL check on its
own before the call.


	Joerg


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