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From: Roland Dreier <roland@purestorage.com>
Date: Fri, 20 Jan 2012 00:23:52 -0800
Message-ID: <CAL1RGDVWDsNhHywkmzaGWxZ5ERYatXVh4fGFC_tmOkkLt3Dg+w@mail.gmail.com>
Subject: Re: kernel BUG at drivers/iommu/intel-iommu.c:1767 on F16 3.1.1-2.fc16.x86_64
To: Albert Strasheim <fullung@gmail.com>
Cc: linux-rdma@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        David Woodhouse <dwmw2@infradead.org>
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On Thu, Jan 19, 2012 at 12:57 AM, Albert Strasheim <fullung@gmail.com> wrote:
> Just checking up on this issue. Is there any further testing or
> information we can provide to help make a fix happen?

I'm not likely to be much help on VT-d issues, but maybe it
would be useful to dump all the values in the BUG_ON if its
going to trigger, ie just before

       BUG_ON(addr_width < BITS_PER_LONG && (iov_pfn + nr_pages - 1)
>> addr_width);

add

       if (addr_width < BITS_PER_LONG && (iov_pfn + nr_pages - 1) >> addr_width)
           pr_err("VT-d BUG! addr_width %d < %d (iov_pfn 0x%lx
nr_pages %ld)\n", addr_width, BITS_PER_LONG, iov_pfn, nr_pages);

and report what that prints.

 - R.