On 27/01/17 18:00, Sricharan wrote:
> Hi Robin,
>
> [..]
>
>>>> +const struct iommu_ops *of_iommu_configure(struct device *dev,
>>>> + struct device_node *master_np)
>>>> +{
>>>> + const struct iommu_ops *ops;
>>>> +
>>>> + if (!master_np)
>>>> + return NULL;
>>>> +
>>>> + if (dev_is_pci(dev))
>>>> + ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
>>>
>>> I gave the whole patch set a try on ThunderX. really_probe() is failing
>>> on dma_configure()->of_pci_iommu_init() for each PCI device.
>>
>> When you say "failing", do you mean cleanly, or with a crash? I've
>> managed to hit __of_match_node() dereferencing NULL from
>> of_iommu_xlate() in a horribly complicated chain of events, which I'm
>> trying to figure out now, and I wonder if the two might be related.
>
> Sorry that there is crash still. __of_match_node seems to checking
> for NULL arguments , feels like some invalid pointer was passed in.
> Is there any particular sequence to try for this ?
Ah, I did figure it out - it wasn't actually a NULL dereference, but an
unmapped address. Turns out __iommu_of_table is in initdata, so any
driver probing after init, connected to an unprobed IOMMU (in this case
disabled in DT), trips over trying to match the now-freed table. I'm
working on the fix - technically the bug's in my patch (#2) anyway ;)
Robin.
>
> Regards,
> Sricharan
>
>
>
>
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