Hello, The dereference on line 342 does not look correct. julia ---------- Forwarded message ---------- Date: Sun, 15 Nov 2020 10:58:55 +0800 From: kernel test robot <lkp(a)intel.com&gt; To: kbuild(a)lists.01.org Cc: lkp(a)intel.com, Julia Lawall <julia.lawall(a)lip6.fr&gt;, Elena Reshetova <elena.reshetova(a)intel.com&gt; Subject: [drm-drm-misc:for-linux-next 986/990] drivers/gpu/drm/drm_atomic_uapi.c:342:23-26: ERROR: crtc is NULL but dereferenced. CC: kbuild-all(a)lists.01.org TO: Simon Ser <contact(a)emersion.fr&gt; CC: Sam Ravnborg <sam(a)ravnborg.org&gt; CC: Daniel Vetter <daniel.vetter(a)ffwll.ch&gt; tree: git://anongit.freedesktop.org/drm/drm-misc for-linux-next head: 5933baa36e267e480bec59a752579c7581b0b2f5 commit: e3aae683e861a987d3d7dca593aaff93ac001bcb [986/990] drm: convert drm_atomic_uapi.c to new debug helpers :::::: branch date: 7 hours ago :::::: commit date: 13 hours ago config: microblaze-randconfig-c004-20201115 (attached as .config) compiler: microblaze-linux-gcc (GCC) 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: Julia Lawall <julia.lawall(a)lip6.fr&gt; "coccinelle warnings: (new ones prefixed by >>)" vim +342 drivers/gpu/drm/drm_atomic_uapi.c 72fdb40c1a4b48f Daniel Vetter 2018-09-05 290 72fdb40c1a4b48f Daniel Vetter 2018-09-05 291 /** 42240c90e3b03de Thierry Reding 2019-12-06 292 * drm_atomic_set_crtc_for_connector - set CRTC for connector 72fdb40c1a4b48f Daniel Vetter 2018-09-05 293 * @conn_state: atomic state object for the connector 42240c90e3b03de Thierry Reding 2019-12-06 294 * @crtc: CRTC to use for the connector 72fdb40c1a4b48f Daniel Vetter 2018-09-05 295 * 42240c90e3b03de Thierry Reding 2019-12-06 296 * Changing the assigned CRTC for a connector requires us to grab the lock and 42240c90e3b03de Thierry Reding 2019-12-06 297 * state for the new CRTC, as needed. This function takes care of all these 72fdb40c1a4b48f Daniel Vetter 2018-09-05 298 * details besides updating the pointer in the state object itself. 72fdb40c1a4b48f Daniel Vetter 2018-09-05 299 * 72fdb40c1a4b48f Daniel Vetter 2018-09-05 300 * Returns: 72fdb40c1a4b48f Daniel Vetter 2018-09-05 301 * 0 on success or can fail with -EDEADLK or -ENOMEM. When the error is EDEADLK 72fdb40c1a4b48f Daniel Vetter 2018-09-05 302 * then the w/w mutex code has detected a deadlock and the entire atomic 72fdb40c1a4b48f Daniel Vetter 2018-09-05 303 * sequence must be restarted. All other errors are fatal. 72fdb40c1a4b48f Daniel Vetter 2018-09-05 304 */ 72fdb40c1a4b48f Daniel Vetter 2018-09-05 305 int 72fdb40c1a4b48f Daniel Vetter 2018-09-05 306 drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, 72fdb40c1a4b48f Daniel Vetter 2018-09-05 307 struct drm_crtc *crtc) 72fdb40c1a4b48f Daniel Vetter 2018-09-05 308 { 72fdb40c1a4b48f Daniel Vetter 2018-09-05 309 struct drm_connector *connector = conn_state->connector; 72fdb40c1a4b48f Daniel Vetter 2018-09-05 310 struct drm_crtc_state *crtc_state; 72fdb40c1a4b48f Daniel Vetter 2018-09-05 311 72fdb40c1a4b48f Daniel Vetter 2018-09-05 312 if (conn_state->crtc == crtc) 72fdb40c1a4b48f Daniel Vetter 2018-09-05 313 return 0; 72fdb40c1a4b48f Daniel Vetter 2018-09-05 314 72fdb40c1a4b48f Daniel Vetter 2018-09-05 315 if (conn_state->crtc) { 72fdb40c1a4b48f Daniel Vetter 2018-09-05 316 crtc_state = drm_atomic_get_new_crtc_state(conn_state->state, 72fdb40c1a4b48f Daniel Vetter 2018-09-05 317 conn_state->crtc); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 318 72fdb40c1a4b48f Daniel Vetter 2018-09-05 319 crtc_state->connector_mask &= 72fdb40c1a4b48f Daniel Vetter 2018-09-05 320 ~drm_connector_mask(conn_state->connector); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 321 72fdb40c1a4b48f Daniel Vetter 2018-09-05 322 drm_connector_put(conn_state->connector); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 323 conn_state->crtc = NULL; 72fdb40c1a4b48f Daniel Vetter 2018-09-05 324 } 72fdb40c1a4b48f Daniel Vetter 2018-09-05 325 72fdb40c1a4b48f Daniel Vetter 2018-09-05 326 if (crtc) { 72fdb40c1a4b48f Daniel Vetter 2018-09-05 327 crtc_state = drm_atomic_get_crtc_state(conn_state->state, crtc); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 328 if (IS_ERR(crtc_state)) 72fdb40c1a4b48f Daniel Vetter 2018-09-05 329 return PTR_ERR(crtc_state); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 330 72fdb40c1a4b48f Daniel Vetter 2018-09-05 331 crtc_state->connector_mask |= 72fdb40c1a4b48f Daniel Vetter 2018-09-05 332 drm_connector_mask(conn_state->connector); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 333 72fdb40c1a4b48f Daniel Vetter 2018-09-05 334 drm_connector_get(conn_state->connector); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 335 conn_state->crtc = crtc; 72fdb40c1a4b48f Daniel Vetter 2018-09-05 336 e3aae683e861a98 Simon Ser 2020-11-11 337 drm_dbg_atomic(crtc->dev, e3aae683e861a98 Simon Ser 2020-11-11 338 "Link [CONNECTOR:%d:%s] state %p to [CRTC:%d:%s]\n", 72fdb40c1a4b48f Daniel Vetter 2018-09-05 339 connector->base.id, connector->name, 72fdb40c1a4b48f Daniel Vetter 2018-09-05 340 conn_state, crtc->base.id, crtc->name); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 341 } else { e3aae683e861a98 Simon Ser 2020-11-11 @342 drm_dbg_atomic(crtc->dev, e3aae683e861a98 Simon Ser 2020-11-11 343 "Link [CONNECTOR:%d:%s] state %p to [NOCRTC]\n", 72fdb40c1a4b48f Daniel Vetter 2018-09-05 344 connector->base.id, connector->name, 72fdb40c1a4b48f Daniel Vetter 2018-09-05 345 conn_state); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 346 } 72fdb40c1a4b48f Daniel Vetter 2018-09-05 347 72fdb40c1a4b48f Daniel Vetter 2018-09-05 348 return 0; 72fdb40c1a4b48f Daniel Vetter 2018-09-05 349 } 72fdb40c1a4b48f Daniel Vetter 2018-09-05 350 EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector); 72fdb40c1a4b48f Daniel Vetter 2018-09-05 351 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org