Zhibin Li's GSoC status report - #2 of 12

[Zhibin Li]

On Tue, Jun 11, 2019 at 6:01 PM Patrik Jakobsson <pjakobsson at suse.de> wrote:

> On Mon, Jun 10, 2019 at 11:49:01PM +0800, Zhibin Li wrote:
> > Hi all,
> >
> > I just finished my final so I didn't do much last week.
> >
> > Accomplishments:
> > - Went through i915 source code to mark down what's missing in the
> original
> > patch set.
> > - Started to test i915 manually. But I came across some problems (I will
> > mention them below in the questions section.
> >
> > Questions:
> > When I started to test i915 ioctls, I found that it can't be integrated
> > into strace's test suite. Please take a look at [1]. It makes sense that
> > Patrik uses the driver name linked to the file descriptor to identify the
> > specific device. After that the matched ioctl decoder will be invoked.
> > Here's my question: Is there any way to tamper the path linked to the fd?
> > Something like injection? I mean we usually use fd = -1 in the test but
> in
> > this case it won't work because a valid driver name has to be obtained
> from
> > the fd. Using -1 will simply match no devices.
> > Or can we tamper the priv_data in struct tcb when we run tests? Because
> the
> > driver name is stored in priv_data.
> > I'm able to test those device specific ioctls by simply returning them.
> For
> > example there is if...else clause to determine which (i915 or something
> > else) decoder to invoke. When I want to test i915, I can temporarily
> remove
> > the if...else and return i915_drm_ioctl(). In this way I can manually
> test
> > if it works.
>
> Hi Zhibin,
> If you store the name of the driver (ie "i915") in tcb_priv_data before
> drm_is_driver() gets called you would skip drm_get_driver_name()
> entirely. Does that solve your problem?
>
> -Patrik
>
> Yes it could work. But for now the problem is how to store the name. I mean
in the test suite there is an option -e inject= for tampering something in
the tcb
but I'm not sure there is an available way to store something in priv_data.
So I'm looking into the injection implementation to see if I can add
support for it.
Any other suggestions from you guys?

> >
> > TODO:
> > - As mentioned above, I'm still looking for a better way to test them.
> > - Add missing functions in i915 decoder.
> >
> > BTW is the IRC logger robot absent? I can't see any logs from [2]
> anymore.
> >
> > [1] https://github.com/haoyouab/strace/blob/stuff/drm.c#L28
> > [2] https://strace.io/logs
> >
> > Thanks,
> > Zhibin Li
>
> > --
> > Strace-devel mailing list
> > Strace-devel at lists.strace.io
> > https://lists.strace.io/mailman/listinfo/strace-devel
>
> --
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