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Fri, 25 Feb 2022 22:59:26 +0000 Date: Sat, 26 Feb 2022 06:59:05 +0800 From: kernel test robot To: Jakob Koschel Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org, Mike Rapoport , linux-kernel@vger.kernel.org, Mike Rapoport Subject: [rppt:kasper 6/6] drivers/gpu/drm/vmwgfx/vmwgfx_kms.c:2623:2: warning: variable 'mode' is used uninitialized whenever 'for' loop exits because its condition is false Message-ID: <202202260631.sb20qmrj-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org tree: https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git kasper head: 7b670b09e6e571dc47d64528131db6c9da12578d commit: 7b670b09e6e571dc47d64528131db6c9da12578d [6/6] treewide: remove check of list iterator against head past the loop body config: i386-randconfig-a013 (https://download.01.org/0day-ci/archive/20220226/202202260631.sb20qmrj-lkp@intel.com/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/commit/?id=7b670b09e6e571dc47d64528131db6c9da12578d git remote add rppt https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git git fetch --no-tags rppt kasper git checkout 7b670b09e6e571dc47d64528131db6c9da12578d # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kernel/ drivers/gpu/drm/vmwgfx/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> drivers/gpu/drm/vmwgfx/vmwgfx_kms.c:2623:2: warning: variable 'mode' is used uninitialized whenever 'for' loop exits because its condition is false [-Wsometimes-uninitialized] list_for_each_entry(tmp2, &con->modes, head) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/list.h:639:7: note: expanded from macro 'list_for_each_entry' !list_entry_is_head(pos, head, member); \ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/vmwgfx/vmwgfx_kms.c:2630:7: note: uninitialized use occurs here if (!mode) { ^~~~ drivers/gpu/drm/vmwgfx/vmwgfx_kms.c:2623:2: note: remove the condition if it is always true list_for_each_entry(tmp2, &con->modes, head) { ^ include/linux/list.h:639:7: note: expanded from macro 'list_for_each_entry' !list_entry_is_head(pos, head, member); \ ^ drivers/gpu/drm/vmwgfx/vmwgfx_kms.c:2588:31: note: initialize the variable 'mode' to silence this warning struct drm_display_mode *mode; ^ = NULL 1 warning generated. vim +2623 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c 2576 2577 int vmw_kms_fbdev_init_data(struct vmw_private *dev_priv, 2578 unsigned unit, 2579 u32 max_width, 2580 u32 max_height, 2581 struct drm_connector **p_con, 2582 struct drm_crtc **p_crtc, 2583 struct drm_display_mode **p_mode) 2584 { 2585 struct drm_connector *con = NULL; 2586 struct drm_connector *tmp1; 2587 struct vmw_display_unit *du; 2588 struct drm_display_mode *mode; 2589 struct drm_display_mode *tmp2; 2590 int i = 0; 2591 int ret = 0; 2592 2593 mutex_lock(&dev_priv->drm.mode_config.mutex); 2594 list_for_each_entry(tmp1, &dev_priv->drm.mode_config.connector_list, 2595 head) { 2596 if (i == unit) { 2597 con = tmp1; 2598 break; 2599 } 2600 2601 ++i; 2602 } 2603 2604 if (!con) { 2605 DRM_ERROR("Could not find initial display unit.\n"); 2606 ret = -EINVAL; 2607 goto out_unlock; 2608 } 2609 2610 if (list_empty(&con->modes)) 2611 (void) vmw_du_connector_fill_modes(con, max_width, max_height); 2612 2613 if (list_empty(&con->modes)) { 2614 DRM_ERROR("Could not find initial display mode.\n"); 2615 ret = -EINVAL; 2616 goto out_unlock; 2617 } 2618 2619 du = vmw_connector_to_du(con); 2620 *p_con = con; 2621 *p_crtc = &du->crtc; 2622 > 2623 list_for_each_entry(tmp2, &con->modes, head) { 2624 if (tmp2->type & DRM_MODE_TYPE_PREFERRED) { 2625 mode = tmp2; 2626 break; 2627 } 2628 } 2629 2630 if (!mode) { 2631 WARN_ONCE(true, "Could not find initial preferred mode.\n"); 2632 *p_mode = list_first_entry(&con->modes, 2633 struct drm_display_mode, 2634 head); 2635 } else { 2636 *p_mode = mode; 2637 } 2638 2639 out_unlock: 2640 mutex_unlock(&dev_priv->drm.mode_config.mutex); 2641 2642 return ret; 2643 } 2644 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org