Hi Lukasz, I love your patch! Perhaps something to improve: url: https://github.com/0day-ci/linux/commits/Lukasz-Luba/Add-support-for-devices-in-the-Energy-Model/20200527-180614 base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next config: i386-randconfig-m021-20200605 (attached as .config) compiler: gcc-9 (Debian 9.3.0-13) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> smatch warnings: kernel/power/energy_model.c:316 em_dev_register_perf_domain() error: we previously assumed 'dev->em_pd' could be null (see line 277) # https://github.com/0day-ci/linux/commit/110d050cb7ba1c96e63ada498979d1fd99529be2 git remote add linux-review https://github.com/0day-ci/linux git remote update linux-review git checkout 110d050cb7ba1c96e63ada498979d1fd99529be2 vim +316 kernel/power/energy_model.c 0e294e607adaf3 Lukasz Luba 2020-05-27 262 int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, 110d050cb7ba1c Lukasz Luba 2020-05-27 263 struct em_data_callback *cb, cpumask_t *cpus) 27871f7a8a341e Quentin Perret 2018-12-03 264 { 27871f7a8a341e Quentin Perret 2018-12-03 265 unsigned long cap, prev_cap = 0; 110d050cb7ba1c Lukasz Luba 2020-05-27 266 int cpu, ret; 27871f7a8a341e Quentin Perret 2018-12-03 267 110d050cb7ba1c Lukasz Luba 2020-05-27 268 if (!dev || !nr_states || !cb) 27871f7a8a341e Quentin Perret 2018-12-03 269 return -EINVAL; 27871f7a8a341e Quentin Perret 2018-12-03 270 27871f7a8a341e Quentin Perret 2018-12-03 271 /* 27871f7a8a341e Quentin Perret 2018-12-03 272 * Use a mutex to serialize the registration of performance domains and 27871f7a8a341e Quentin Perret 2018-12-03 273 * let the driver-defined callback functions sleep. 27871f7a8a341e Quentin Perret 2018-12-03 274 */ 27871f7a8a341e Quentin Perret 2018-12-03 275 mutex_lock(&em_pd_mutex); 27871f7a8a341e Quentin Perret 2018-12-03 276 110d050cb7ba1c Lukasz Luba 2020-05-27 @277 if (dev->em_pd) { ^^^^^^^^^^ Check for NULL. 27871f7a8a341e Quentin Perret 2018-12-03 278 ret = -EEXIST; 27871f7a8a341e Quentin Perret 2018-12-03 279 goto unlock; 27871f7a8a341e Quentin Perret 2018-12-03 280 } 27871f7a8a341e Quentin Perret 2018-12-03 281 110d050cb7ba1c Lukasz Luba 2020-05-27 282 if (_is_cpu_device(dev)) { 110d050cb7ba1c Lukasz Luba 2020-05-27 283 if (!cpus) { 110d050cb7ba1c Lukasz Luba 2020-05-27 284 dev_err(dev, "EM: invalid CPU mask\n"); 110d050cb7ba1c Lukasz Luba 2020-05-27 285 ret = -EINVAL; 110d050cb7ba1c Lukasz Luba 2020-05-27 286 goto unlock; 110d050cb7ba1c Lukasz Luba 2020-05-27 287 } 110d050cb7ba1c Lukasz Luba 2020-05-27 288 110d050cb7ba1c Lukasz Luba 2020-05-27 289 for_each_cpu(cpu, cpus) { 110d050cb7ba1c Lukasz Luba 2020-05-27 290 if (em_cpu_get(cpu)) { 110d050cb7ba1c Lukasz Luba 2020-05-27 291 dev_err(dev, "EM: exists for CPU%d\n", cpu); 110d050cb7ba1c Lukasz Luba 2020-05-27 292 ret = -EEXIST; 110d050cb7ba1c Lukasz Luba 2020-05-27 293 goto unlock; 110d050cb7ba1c Lukasz Luba 2020-05-27 294 } 27871f7a8a341e Quentin Perret 2018-12-03 295 /* 110d050cb7ba1c Lukasz Luba 2020-05-27 296 * All CPUs of a domain must have the same 110d050cb7ba1c Lukasz Luba 2020-05-27 297 * micro-architecture since they all share the same 110d050cb7ba1c Lukasz Luba 2020-05-27 298 * table. 27871f7a8a341e Quentin Perret 2018-12-03 299 */ 8ec59c0f5f4966 Vincent Guittot 2019-06-17 300 cap = arch_scale_cpu_capacity(cpu); 27871f7a8a341e Quentin Perret 2018-12-03 301 if (prev_cap && prev_cap != cap) { 110d050cb7ba1c Lukasz Luba 2020-05-27 302 dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n", 110d050cb7ba1c Lukasz Luba 2020-05-27 303 cpumask_pr_args(cpus)); 110d050cb7ba1c Lukasz Luba 2020-05-27 304 27871f7a8a341e Quentin Perret 2018-12-03 305 ret = -EINVAL; 27871f7a8a341e Quentin Perret 2018-12-03 306 goto unlock; 27871f7a8a341e Quentin Perret 2018-12-03 307 } 27871f7a8a341e Quentin Perret 2018-12-03 308 prev_cap = cap; 27871f7a8a341e Quentin Perret 2018-12-03 309 } 110d050cb7ba1c Lukasz Luba 2020-05-27 310 } 27871f7a8a341e Quentin Perret 2018-12-03 311 110d050cb7ba1c Lukasz Luba 2020-05-27 312 ret = em_create_pd(dev, nr_states, cb, cpus); If it's a _is_cpu_device() then it iterates through a bunch of devices and sets up cpu_dev->em_pd for each. Presumably one of the devices is "dev" or this would crash pretty early on in testing? 110d050cb7ba1c Lukasz Luba 2020-05-27 313 if (ret) 27871f7a8a341e Quentin Perret 2018-12-03 314 goto unlock; 27871f7a8a341e Quentin Perret 2018-12-03 315 110d050cb7ba1c Lukasz Luba 2020-05-27 @316 em_debug_create_pd(dev); ^^^ Dereferences dev->em_pd. 110d050cb7ba1c Lukasz Luba 2020-05-27 317 dev_info(dev, "EM: created perf domain\n"); 27871f7a8a341e Quentin Perret 2018-12-03 318 27871f7a8a341e Quentin Perret 2018-12-03 319 unlock: 27871f7a8a341e Quentin Perret 2018-12-03 320 mutex_unlock(&em_pd_mutex); 27871f7a8a341e Quentin Perret 2018-12-03 321 return ret; 27871f7a8a341e Quentin Perret 2018-12-03 322 } 0e294e607adaf3 Lukasz Luba 2020-05-27 323 EXPORT_SYMBOL_GPL(em_dev_register_perf_domain); --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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