Re: [Regression] [PATCH] iommu: Avoid crash in init_no_remapping_devices if iommu is NULL

[Lu Baolu <baolu.lu@linux.intel.com>]

hi Torsten,

On 9/1/20 10:41 PM, Torsten Hilbrich wrote:
> On 01.09.20 04:02, Lu Baolu wrote:
> [...]
>> This looks more like a generic issue, used-before-allocated, and should
>> be fixed in iommu.c instead of VT-d driver. How about
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 8fd93a5b8764..a599da87eb60 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -190,6 +190,28 @@ static void dev_iommu_free(struct device *dev)
>>          dev->iommu = NULL;
>>   }
>>
>> +void *dev_iommu_priv_get(struct device *dev)
>> +{
>> +       struct dev_iommu *param = dev_iommu_get(dev);
>> +
>> +       if (WARN_ON(!param))
>> +               return ERR_PTR(-ENOMEM);
>> +
>> +        return param->priv;
>> +}
>> +EXPORT_SYMBOL_GPL(dev_iommu_priv_get);
>> +
>> +void dev_iommu_priv_set(struct device *dev, void *priv)
>> +{
>> +       struct dev_iommu *param = dev_iommu_get(dev);
>> +
>> +       if (WARN_ON(!param))
>> +               return;
>> +
>> +        param->priv = priv;
>> +}
>> +EXPORT_SYMBOL_GPL(dev_iommu_priv_set);
>> +
> 
> This fix would work in my case. I tested it with slight modification to
> replace the inline routines in include/linux/iommu.h.
> 
> The WARN_ON was not triggered during my tests. However, looking at the
> definition of dev_iommu_get this is to be expected.

So I suppose you will post a new version. :-)

Best regards,
baolu
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