Re: [PATCH v4 11/18] PM: EM: Add runtime update interface to modify EM power

[kernel test robot]

Hi Lukasz,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on rafael-pm/thermal linus/master v6.6-rc3 next-20230926]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Lukasz-Luba/PM-EM-Add-missing-newline-for-the-message-log/20230925-181243
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20230925081139.1305766-12-lukasz.luba%40arm.com
patch subject: [PATCH v4 11/18] PM: EM: Add runtime update interface to modify EM power
config: i386-randconfig-063-20230926 (https://download.01.org/0day-ci/archive/20230927/202309270106.c56Z2Tci-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230927/202309270106.c56Z2Tci-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309270106.c56Z2Tci-lkp@xxxxxxxxx/

sparse warnings: (new ones prefixed by >>)
   kernel/power/energy_model.c:125:13: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct em_perf_table *tmp @@     got struct em_perf_table [noderef] __rcu *runtime_table @@
   kernel/power/energy_model.c:125:13: sparse:     expected struct em_perf_table *tmp
   kernel/power/energy_model.c:125:13: sparse:     got struct em_perf_table [noderef] __rcu *runtime_table
>> kernel/power/energy_model.c:613:27: sparse: sparse: incompatible types in comparison expression (different address spaces):
>> kernel/power/energy_model.c:613:27: sparse:    struct em_perf_table [noderef] __rcu *
>> kernel/power/energy_model.c:613:27: sparse:    struct em_perf_table *

vim +613 kernel/power/energy_model.c

   569	
   570	/**
   571	 * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
   572	 * @dev		: Device for which the EM is registered
   573	 *
   574	 * Unregister the EM for the specified @dev (but not a CPU device).
   575	 */
   576	void em_dev_unregister_perf_domain(struct device *dev)
   577	{
   578		struct em_perf_table __rcu *runtime_table;
   579		struct em_perf_domain *pd;
   580	
   581		if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
   582			return;
   583	
   584		if (_is_cpu_device(dev))
   585			return;
   586	
   587		pd = dev->em_pd;
   588		/*
   589		 * The mutex separates all register/unregister requests and protects
   590		 * from potential clean-up/setup issues in the debugfs directories.
   591		 * The debugfs directory name is the same as device's name.
   592		 * The lock also protects the updater of the runtime modifiable
   593		 * EM and this remover.
   594		 */
   595		mutex_lock(&em_pd_mutex);
   596	
   597		em_debug_remove_pd(dev);
   598	
   599		runtime_table = pd->runtime_table;
   600	
   601		/*
   602		 * Safely destroy runtime modifiable EM. By using the call
   603		 * synchronize_rcu() we make sure we don't progress till last user
   604		 * finished the RCU section and our update got applied.
   605		 */
   606		rcu_assign_pointer(pd->runtime_table, NULL);
   607		synchronize_rcu();
   608	
   609		/*
   610		 * After the sync no updates will be in-flight, so free the
   611		 * memory allocated for runtime table (if there was such).
   612		 */
 > 613		if (runtime_table != pd->default_table) {

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