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SubjectRe: [PATCH] iommu/amd: Check if domain is NULL before dereference it
On Thu, Aug 24, 2017 at 08:47:33PM +0800, Baoquan He wrote:
> On 08/24/17 at 03:32pm, Dan Carpenter wrote:
> > Take a look at this code for example. But all the places which call
> > get_domain() are the same:
> >
> > drivers/iommu/amd_iommu.c
> > 2648 page = virt_to_page(virt_addr);
> > 2649 size = PAGE_ALIGN(size);
> > 2650
> > 2651 domain = get_domain(dev);
> > ^^^^^^^^^^^^^^
> > imagined get_domain() returns NULL.
> >
> > 2652 if (IS_ERR(domain))
> > 2653 goto free_mem;
> > 2654
> > 2655 dma_dom = to_dma_ops_domain(domain);
> > ^^^^^^^^^^^^^^^^^^^^^^^^^
> > This will Oops.
>
> I see, it's a problem. Thanks for telling!
>
> How about below change? But I am not very sure which errno should be
> picked, seems the latter one, EBUSY is better since it has passed the
> check_device() checking.

Looks good to me. You know better than I do which errno is best, so
I'll leave that to you.

regards,
dan carpenter

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