Hi Ziyang, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on rafael-pm/thermal] [also build test WARNING on v5.15-rc5 next-20211013] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Ziyang-Xuan/thermal-core-fix-a-U... base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git thermal config: hexagon-randconfig-r005-20211014 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6c76d0101193aa4eb891a6954ff047eda2f9cf71) 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://github.com/0day-ci/linux/commit/fb39770678d4d898891ede9121c811844... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ziyang-Xuan/thermal-core-fix-a-UAF-bug-in-__thermal_cooling_device_register/20211014-164859 git checkout fb39770678d4d898891ede9121c811844b5f2890 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=hexagon If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): if (id < 0) ^~~~~~ drivers/thermal/thermal_core.c:949:17: note: uninitialized use occurs here return ERR_PTR(ret); ^~~ drivers/thermal/thermal_core.c:901:2: note: remove the 'if' if its condition is always false if (id < 0) ^~~~~~~~~~~ drivers/thermal/thermal_core.c:890:13: note: initialize the variable 'ret' to silence this warning int id, ret; ^ = 0 1 warning generated. vim +901 drivers/thermal/thermal_core.c 866 867 /** 868 * __thermal_cooling_device_register() - register a new thermal cooling device 869 * @np: a pointer to a device tree node. 870 * @type: the thermal cooling device type. 871 * @devdata: device private data. 872 * @ops: standard thermal cooling devices callbacks. 873 * 874 * This interface function adds a new thermal cooling device (fan/processor/...) 875 * to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself 876 * to all the thermal zone devices registered at the same time. 877 * It also gives the opportunity to link the cooling device to a device tree 878 * node, so that it can be bound to a thermal zone created out of device tree. 879 * 880 * Return: a pointer to the created struct thermal_cooling_device or an 881 * ERR_PTR. Caller must check return value with IS_ERR*() helpers. 882 */ 883 static struct thermal_cooling_device * 884 __thermal_cooling_device_register(struct device_node *np, 885 const char *type, void *devdata, 886 const struct thermal_cooling_device_ops *ops) 887 { 888 struct thermal_cooling_device *cdev; 889 struct thermal_zone_device *pos = NULL; 890 int id, ret; 891 892 if (!ops || !ops->get_max_state || !ops->get_cur_state || 893 !ops->set_cur_state) 894 return ERR_PTR(-EINVAL); 895 896 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); 897 if (!cdev) 898 return ERR_PTR(-ENOMEM); 899 900 id = ida_simple_get(&thermal_cdev_ida, 0, 0, GFP_KERNEL); 902 goto out_kfree_cdev; 903 cdev->id = id; 904 905 cdev->type = kstrdup(type ? type : "", GFP_KERNEL); 906 if (!cdev->type) { 907 ret = -ENOMEM; 908 goto out_ida_remove; 909 } 910 911 mutex_init(&cdev->lock); 912 INIT_LIST_HEAD(&cdev->thermal_instances); 913 cdev->np = np; 914 cdev->ops = ops; 915 cdev->updated = false; 916 cdev->device.class = &thermal_class; 917 cdev->devdata = devdata; 918 thermal_cooling_device_setup_sysfs(cdev); 919 dev_set_name(&cdev->device, "cooling_device%d", cdev->id); 920 ret = device_register(&cdev->device); 921 if (ret) 922 goto out_kfree_type; 923 924 /* Add 'this' new cdev to the global cdev list */ 925 mutex_lock(&thermal_list_lock); 926 list_add(&cdev->node, &thermal_cdev_list); 927 mutex_unlock(&thermal_list_lock); 928 929 /* Update binding information for 'this' new cdev */ 930 bind_cdev(cdev); 931 932 mutex_lock(&thermal_list_lock); 933 list_for_each_entry(pos, &thermal_tz_list, node) 934 if (atomic_cmpxchg(&pos->need_update, 1, 0)) 935 thermal_zone_device_update(pos, 936 THERMAL_EVENT_UNSPECIFIED); 937 mutex_unlock(&thermal_list_lock); 938 939 return cdev; 940 941 out_kfree_type: 942 kfree(cdev->type); 943 put_device(&cdev->device); 944 cdev = NULL; 945 out_ida_remove: 946 ida_simple_remove(&thermal_cdev_ida, id); 947 out_kfree_cdev: 948 kfree(cdev); 949 return ERR_PTR(ret); 950 } 951 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org