[bug report] drm/vmwgfx: Use new validation interface for the modesetting code v2

[Dan Carpenter]

Hello Thomas Hellstrom,

The patch 2724b2d54cda: "drm/vmwgfx: Use new validation interface for
the modesetting code v2" from Sep 26, 2018, leads to the following
static checker warning:

	drivers/gpu/drm/vmwgfx/vmwgfx_kms.c:2606 vmw_kms_helper_validation_finish()
	error: uninitialized symbol 'handle'.

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
  2587  void vmw_kms_helper_validation_finish(struct vmw_private *dev_priv,
  2588                                        struct drm_file *file_priv,
  2589                                        struct vmw_validation_context *ctx,
  2590                                        struct vmw_fence_obj **out_fence,
  2591                                        struct drm_vmw_fence_rep __user *
  2592                                        user_fence_rep)
  2593  {
  2594          struct vmw_fence_obj *fence = NULL;
  2595          uint32_t handle;
  2596          int ret;
  2597  
  2598          if (file_priv || user_fence_rep || vmw_validation_has_bos(ctx) ||
  2599              out_fence)
  2600                  ret = vmw_execbuf_fence_commands(file_priv, dev_priv, &fence,
  2601                                                   file_priv ? &handle : NULL);
  2602          vmw_validation_done(ctx, fence);
  2603          if (file_priv)
  2604                  vmw_execbuf_copy_fence_user(dev_priv, vmw_fpriv(file_priv),
  2605                                              ret, user_fence_rep, fence,
                                                    ^^^
  2606                                              handle, -1, NULL);
                                                    ^^^^^^

So instead of handling vmw_execbuf_fence_commands() errors here, we pass
it to vmw_execbuf_copy_fence_user() which presumably does the right
thing.  But the warning is correct that "handle" can be uninitialized
here.

  2607          if (out_fence)
  2608                  *out_fence = fence;
  2609          else
  2610                  vmw_fence_obj_unreference(&fence);
  2611  }



regards,
dan carpenter