[Intel-gfx] [PATCH i-g-t] kms_cursor_crc: Kernel now checks for integer overflow

[Matt Roper]

On Tue, Feb 03, 2015 at 04:33:51PM +0200, Jani Nikula wrote:
> On Tue, 03 Feb 2015, Matt Roper <matthew.d.roper at intel.com> wrote:
> > As of kernel commit
> >
> >     commit a679064a7e9e8799177a64a31668a34a1bc6a4f1
> >     Author: Matt Roper <matthew.d.roper at intel.com>
> >     Date:   Fri Jan 30 16:22:37 2015 -0800
> >
> >         drm/i915: Switch planes from transitional helpers to full atomic helpers
> >
> > the kernel now checks for cursor coordinates that would result in
> > integer overflow and returns -ERANGE, similar to the checking that was
> > already done for other plane types.  We update kms_cursor_crc here to
> > reflect this small behavior change:
> >  * Check for success at extreme boundary conditions INT_MAX-{width,height}
> >    rather than INT_MAX
> >  * Add new check for success at SHRT_MAX; if the driver were to
> >    internally use short values and overflow, we could have the cursor
> >    reappear on the screen.
> >  * Add a test for failure with proper error code at INT_MAX-{width,height}+1
> >
> > Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> 
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88917
> 
> ?

Yep, this should fix that one.  Good catch.


Matt

> 
> 
> > ---
> >  tests/kms_cursor_crc.c | 29 ++++++++++++++++++++++++++++-
> >  1 file changed, 28 insertions(+), 1 deletion(-)
> >
> > diff --git a/tests/kms_cursor_crc.c b/tests/kms_cursor_crc.c
> > index e1390a7..64fea12 100644
> > --- a/tests/kms_cursor_crc.c
> > +++ b/tests/kms_cursor_crc.c
> > @@ -139,6 +139,29 @@ static void do_single_test(data_t *data, int x, int y)
> >  	igt_assert(igt_crc_equal(&crc, &ref_crc));
> >  }
> >  
> > +static void do_fail_test(data_t *data, int x, int y, int expect)
> > +{
> > +	igt_display_t *display = &data->display;
> > +	igt_plane_t *cursor;
> > +	cairo_t *cr = igt_get_cairo_ctx(data->drm_fd, &data->primary_fb);
> > +	int ret;
> > +
> > +	igt_print_activity();
> > +
> > +	/* Hardware test */
> > +	igt_paint_test_pattern(cr, data->screenw, data->screenh);
> > +	cursor_enable(data);
> > +	cursor = igt_output_get_plane(data->output, IGT_PLANE_CURSOR);
> > +	igt_plane_set_position(cursor, x, y);
> > +	ret = igt_display_try_commit2(display, COMMIT_LEGACY);
> > +
> > +	igt_plane_set_position(cursor, 0, 0);
> > +	cursor_disable(data);
> > +	igt_display_commit(display);
> > +
> > +	igt_assert(ret == expect);
> > +}
> > +
> >  static void do_test(data_t *data,
> >  		    int left, int right, int top, int bottom)
> >  {
> > @@ -201,7 +224,11 @@ static void test_crc_offscreen(data_t *data)
> >  	do_test(data, left - (cursor_w+512), right + (cursor_w+512), top - (cursor_h+512), bottom + (cursor_h+512));
> >  
> >  	/* go nuts */
> > -	do_test(data, INT_MIN, INT_MAX, INT_MIN, INT_MAX);
> > +	do_test(data, INT_MIN, INT_MAX - cursor_w, INT_MIN, INT_MAX - cursor_h);
> > +	do_test(data, SHRT_MIN, SHRT_MAX, SHRT_MIN, SHRT_MAX);
> > +
> > +	/* Make sure we get -ERANGE on integer overflow */
> > +	do_fail_test(data, INT_MAX - cursor_w + 1, INT_MAX - cursor_h + 1, -ERANGE);
> >  }
> >  
> >  static void test_crc_sliding(data_t *data)
> > -- 
> > 1.8.5.1
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795