[Intel-gfx] [bug report] drm/i915: Fill different pages of the GTT

[Dan Carpenter]

Hello Chris Wilson,

The patch 6e32ab3d4777: "drm/i915: Fill different pages of the GTT"
from Feb 13, 2017, leads to the following static checker warning:

	drivers/gpu/drm/i915/selftests/i915_gem_gtt.c:583 walk_hole()
	error: 'vma' dereferencing possible ERR_PTR()

drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
   539                  vma = i915_vma_instance(obj, vm, NULL);
   540                  if (IS_ERR(vma)) {
                            ^^^^^^^^^^
   541                          err = PTR_ERR(vma);
   542                          goto err;
                                ^^^^^^^^^
   543                  }
   544  
   545                  for (addr = hole_start;
   546                       addr + obj->base.size < hole_end;
   547                       addr += obj->base.size) {
   548                          err = i915_vma_pin(vma, 0, 0, addr | flags);
   549                          if (err) {
   550                                  pr_err("%s bind failed at %llx + %llx [hole %llx- %llx] with err=%d\n",
   551                                         __func__, addr, vma->size,
   552                                         hole_start, hole_end, err);
   553                                  goto err;
   554                          }
   555                          i915_vma_unpin(vma);
   556  
   557                          if (!drm_mm_node_allocated(&vma->node) ||
   558                              i915_vma_misplaced(vma, 0, 0, addr | flags)) {
   559                                  pr_err("%s incorrect at %llx + %llx\n",
   560                                         __func__, addr, vma->size);
   561                                  err = -EINVAL;
   562                                  goto err;
   563                          }
   564  
   565                          err = i915_vma_unbind(vma);
   566                          if (err) {
   567                                  pr_err("%s unbind failed at %llx + %llx  with err=%d\n",
   568                                         __func__, addr, vma->size, err);
   569                                  goto err;
   570                          }
   571  
   572                          GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
   573  
   574                          if (igt_timeout(end_time,
   575                                          "%s timed out at %llx\n",
   576                                          __func__, addr)) {
   577                                  err = -EINTR;
   578                                  goto err;
   579                          }
   580                  }
   581  
   582  err:
   583                  if (!i915_vma_is_ggtt(vma))
                             ^^^^^^^^^^^^^^^^^^^^^
Dereferenced inside function call.

regards,
dan carpenter