[kbuild-all] [drm-drm-intel:drm-intel-next 7/8] drivers/gpu/drm/i915/display/skl_scaler.c:253 skl_update_scaler_plane() error: we previously assumed 'fb' could be null (see line 237)

Monday, 15 February 2021

tree:   git://anongit.freedesktop.org/drm/drm-intel drm-intel-next
head:   81637a6ede89b95b6ea7b2f8c594676881110890
commit: 714b1cdb02ee670be1ec5b1190377fef3845acd9 [7/8] drm/i915: refactor skylake scaler
code into new file.
config: x86_64-randconfig-m031-20210211 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com&gt;
Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt;

smatch warnings:
drivers/gpu/drm/i915/display/skl_scaler.c:253 skl_update_scaler_plane() error: we
previously assumed 'fb' could be null (see line 237)

vim +/fb +253 drivers/gpu/drm/i915/display/skl_scaler.c

714b1cdb02ee67 Dave Airlie 2021-02-05  213  int skl_update_scaler_plane(struct
intel_crtc_state *crtc_state,
714b1cdb02ee67 Dave Airlie 2021-02-05  214  			    struct intel_plane_state *plane_state)
714b1cdb02ee67 Dave Airlie 2021-02-05  215  {
714b1cdb02ee67 Dave Airlie 2021-02-05  216  	struct intel_plane *intel_plane =
714b1cdb02ee67 Dave Airlie 2021-02-05  217  		to_intel_plane(plane_state->uapi.plane);
714b1cdb02ee67 Dave Airlie 2021-02-05  218  	struct drm_i915_private *dev_priv =
to_i915(intel_plane->base.dev);
714b1cdb02ee67 Dave Airlie 2021-02-05  219  	struct drm_framebuffer *fb =
plane_state->hw.fb;
714b1cdb02ee67 Dave Airlie 2021-02-05  220  	int ret;
714b1cdb02ee67 Dave Airlie 2021-02-05  221  	bool force_detach = !fb ||
!plane_state->uapi.visible;

All this code assumes "fb" can be NULL.

714b1cdb02ee67 Dave Airlie 2021-02-05  222  	bool need_scaler = false;
714b1cdb02ee67 Dave Airlie 2021-02-05  223  
714b1cdb02ee67 Dave Airlie 2021-02-05  224  	/* Pre-gen11 and SDR planes always need a
scaler for planar formats. */
714b1cdb02ee67 Dave Airlie 2021-02-05  225  	if (!icl_is_hdr_plane(dev_priv,
intel_plane->id) &&
714b1cdb02ee67 Dave Airlie 2021-02-05  226  	    fb &&
intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier))
714b1cdb02ee67 Dave Airlie 2021-02-05  227  		need_scaler = true;
714b1cdb02ee67 Dave Airlie 2021-02-05  228  
714b1cdb02ee67 Dave Airlie 2021-02-05  229  	ret = skl_update_scaler(crtc_state,
force_detach,
714b1cdb02ee67 Dave Airlie 2021-02-05  230 
				drm_plane_index(&intel_plane->base),
714b1cdb02ee67 Dave Airlie 2021-02-05  231  				&plane_state->scaler_id,
714b1cdb02ee67 Dave Airlie 2021-02-05  232 
				drm_rect_width(&plane_state->uapi.src) >> 16,
714b1cdb02ee67 Dave Airlie 2021-02-05  233 
				drm_rect_height(&plane_state->uapi.src) >> 16,
714b1cdb02ee67 Dave Airlie 2021-02-05  234 
				drm_rect_width(&plane_state->uapi.dst),
714b1cdb02ee67 Dave Airlie 2021-02-05  235 
				drm_rect_height(&plane_state->uapi.dst),
714b1cdb02ee67 Dave Airlie 2021-02-05  236  				fb ? fb->format : NULL,
714b1cdb02ee67 Dave Airlie 2021-02-05 @237  				fb ? fb->modifier : 0,
714b1cdb02ee67 Dave Airlie 2021-02-05  238  				need_scaler);
714b1cdb02ee67 Dave Airlie 2021-02-05  239  
714b1cdb02ee67 Dave Airlie 2021-02-05  240  	if (ret || plane_state->scaler_id < 0)
714b1cdb02ee67 Dave Airlie 2021-02-05  241  		return ret;
714b1cdb02ee67 Dave Airlie 2021-02-05  242  
714b1cdb02ee67 Dave Airlie 2021-02-05  243  	/* check colorkey */
714b1cdb02ee67 Dave Airlie 2021-02-05  244  	if (plane_state->ckey.flags) {
714b1cdb02ee67 Dave Airlie 2021-02-05  245  		drm_dbg_kms(&dev_priv->drm,
714b1cdb02ee67 Dave Airlie 2021-02-05  246  			    "[PLANE:%d:%s] scaling with color
key not allowed",
714b1cdb02ee67 Dave Airlie 2021-02-05  247  			    intel_plane->base.base.id,
714b1cdb02ee67 Dave Airlie 2021-02-05  248  			    intel_plane->base.name);
714b1cdb02ee67 Dave Airlie 2021-02-05  249  		return -EINVAL;
714b1cdb02ee67 Dave Airlie 2021-02-05  250  	}
714b1cdb02ee67 Dave Airlie 2021-02-05  251  
714b1cdb02ee67 Dave Airlie 2021-02-05  252  	/* Check src format */
714b1cdb02ee67 Dave Airlie 2021-02-05 @253  	switch (fb->format->format) {
                                                        ^^^^^^^^^^^^
Unchecked dereference.

714b1cdb02ee67 Dave Airlie 2021-02-05  254  	case DRM_FORMAT_RGB565:
714b1cdb02ee67 Dave Airlie 2021-02-05  255  	case DRM_FORMAT_XBGR8888:
714b1cdb02ee67 Dave Airlie 2021-02-05  256  	case DRM_FORMAT_XRGB8888:
714b1cdb02ee67 Dave Airlie 2021-02-05  257  	case DRM_FORMAT_ABGR8888:
714b1cdb02ee67 Dave Airlie 2021-02-05  258  	case DRM_FORMAT_ARGB8888:
714b1cdb02ee67 Dave Airlie 2021-02-05  259  	case DRM_FORMAT_XRGB2101010:
714b1cdb02ee67 Dave Airlie 2021-02-05  260  	case DRM_FORMAT_XBGR2101010:
714b1cdb02ee67 Dave Airlie 2021-02-05  261  	case DRM_FORMAT_ARGB2101010:
714b1cdb02ee67 Dave Airlie 2021-02-05  262  	case DRM_FORMAT_ABGR2101010:
714b1cdb02ee67 Dave Airlie 2021-02-05  263  	case DRM_FORMAT_YUYV:
714b1cdb02ee67 Dave Airlie 2021-02-05  264  	case DRM_FORMAT_YVYU:
714b1cdb02ee67 Dave Airlie 2021-02-05  265  	case DRM_FORMAT_UYVY:
714b1cdb02ee67 Dave Airlie 2021-02-05  266  	case DRM_FORMAT_VYUY:
714b1cdb02ee67 Dave Airlie 2021-02-05  267  	case DRM_FORMAT_NV12:
714b1cdb02ee67 Dave Airlie 2021-02-05  268  	case DRM_FORMAT_XYUV8888:
714b1cdb02ee67 Dave Airlie 2021-02-05  269  	case DRM_FORMAT_P010:
714b1cdb02ee67 Dave Airlie 2021-02-05  270  	case DRM_FORMAT_P012:
714b1cdb02ee67 Dave Airlie 2021-02-05  271  	case DRM_FORMAT_P016:
714b1cdb02ee67 Dave Airlie 2021-02-05  272  	case DRM_FORMAT_Y210:
714b1cdb02ee67 Dave Airlie 2021-02-05  273  	case DRM_FORMAT_Y212:
714b1cdb02ee67 Dave Airlie 2021-02-05  274  	case DRM_FORMAT_Y216:
714b1cdb02ee67 Dave Airlie 2021-02-05  275  	case DRM_FORMAT_XVYU2101010:
714b1cdb02ee67 Dave Airlie 2021-02-05  276  	case DRM_FORMAT_XVYU12_16161616:
714b1cdb02ee67 Dave Airlie 2021-02-05  277  	case DRM_FORMAT_XVYU16161616:
714b1cdb02ee67 Dave Airlie 2021-02-05  278  		break;
714b1cdb02ee67 Dave Airlie 2021-02-05  279  	case DRM_FORMAT_XBGR16161616F:
714b1cdb02ee67 Dave Airlie 2021-02-05  280  	case DRM_FORMAT_ABGR16161616F:
714b1cdb02ee67 Dave Airlie 2021-02-05  281  	case DRM_FORMAT_XRGB16161616F:
714b1cdb02ee67 Dave Airlie 2021-02-05  282  	case DRM_FORMAT_ARGB16161616F:
714b1cdb02ee67 Dave Airlie 2021-02-05  283  		if (INTEL_GEN(dev_priv) >= 11)
714b1cdb02ee67 Dave Airlie 2021-02-05  284  			break;
714b1cdb02ee67 Dave Airlie 2021-02-05  285  		fallthrough;
714b1cdb02ee67 Dave Airlie 2021-02-05  286  	default:
714b1cdb02ee67 Dave Airlie 2021-02-05  287  		drm_dbg_kms(&dev_priv->drm,
714b1cdb02ee67 Dave Airlie 2021-02-05  288  			    "[PLANE:%d:%s] FB:%d unsupported
scaling format 0x%x\n",
714b1cdb02ee67 Dave Airlie 2021-02-05  289  			    intel_plane->base.base.id,
intel_plane->base.name,
714b1cdb02ee67 Dave Airlie 2021-02-05  290  			    fb->base.id,
fb->format->format);
714b1cdb02ee67 Dave Airlie 2021-02-05  291  		return -EINVAL;
714b1cdb02ee67 Dave Airlie 2021-02-05  292  	}
714b1cdb02ee67 Dave Airlie 2021-02-05  293  
714b1cdb02ee67 Dave Airlie 2021-02-05  294  	return 0;
714b1cdb02ee67 Dave Airlie 2021-02-05  295  }

---
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[kbuild-all] [drm-drm-intel:drm-intel-next 7/8] drivers/gpu/drm/i915/display/skl_scaler.c:253 skl_update_scaler_plane() error: we previously assumed 'fb' could be null (see line 237)