Re: [PATCH 1/1] drm/i915: shorten i915_next_seqno debugfs output

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Kees Cook <keescook@chromium.org> writes:

> On Thu, Apr 11, 2013 at 6:22 AM, Mika Kuoppala
> <mika.kuoppala@linux.intel.com> wrote:
>> commit 647416f9eefe7699754b01b9fc82758fde83248c
>> Author: Kees Cook <keescook@chromium.org>
>> Date:   Sun Mar 10 14:10:06 2013 -0700
>>
>>     drm/i915: use simple attribute in debugfs routines
>>
>> made i915_next_seqno debugfs entry to crop it's output
>> if returned value was large enough. Using simple_attr
>> will limit the output to 24 bytes. Fix this by returning
>> only the value and nothing else.
>>
>> Cc: Kees Cook <keescook@chromium.org>
>> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
>
> Oh! Thanks for catching that. What a weird limitation.
>
> What about max freq, min freq, and wedged? Do those run the risk of
> truncation too?

max and min freq should be safe, and wedged too on 32bit platforms.
But if gpu is declared wedged on host with 64bit atomic_t,
it will crop the output.

-Mika