Re: [PATCH 1/7] kernel/cgroup: Add "dev" memory accounting cgroup

[kernel test robot <lkp@intel.com>]

Hi Maarten,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm/drm-next]
[also build test WARNING on drm-exynos/exynos-drm-next linus/master v6.12-rc4 next-20241024]
[cannot apply to tj-cgroup/for-next drm-xe/drm-xe-next akpm-mm/mm-everything drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-misc/drm-misc-next drm-tip/drm-tip]
[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/Maarten-Lankhorst/kernel-cgroup-Add-dev-memory-accounting-cgroup/20241023-155504
base:   git://anongit.freedesktop.org/drm/drm drm-next
patch link:    https://lore.kernel.org/r/20241023075302.27194-2-maarten.lankhorst%40linux.intel.com
patch subject: [PATCH 1/7] kernel/cgroup: Add "dev" memory accounting cgroup
config: i386-randconfig-061-20241025 (https://download.01.org/0day-ci/archive/20241025/202410251311.OLEnaBoD-lkp@intel.com/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/20241025/202410251311.OLEnaBoD-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410251311.OLEnaBoD-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> kernel/cgroup/dev.c:423:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/cgroup/dev.c:423:9: sparse:    struct list_head [noderef] __rcu *
   kernel/cgroup/dev.c:423:9: sparse:    struct list_head *
>> kernel/cgroup/dev.c:423:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/cgroup/dev.c:423:9: sparse:    struct list_head [noderef] __rcu *
   kernel/cgroup/dev.c:423:9: sparse:    struct list_head *
   kernel/cgroup/dev.c: note: in included file (through include/linux/smp.h, include/linux/lockdep.h, include/linux/spinlock.h, ...):
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true

vim +423 kernel/cgroup/dev.c

   400	
   401	/**
   402	 * dev_cgroup_unregister_device() - Unregister a previously registered device.
   403	 * @cgdev: The device to unregister.
   404	 *
   405	 * This function undoes dev_cgroup_register_device.
   406	 */
   407	void dev_cgroup_unregister_device(struct dev_cgroup_device *cgdev)
   408	{
   409		struct devcg_device *dev;
   410		struct list_head *entry;
   411	
   412		if (!cgdev || !cgdev->priv)
   413			return;
   414	
   415		dev = cgdev->priv;
   416		cgdev->priv = NULL;
   417	
   418		spin_lock(&devcg_lock);
   419	
   420		/* Remove from global device list */
   421		list_del_rcu(&dev->dev_node);
   422	
 > 423		list_for_each_rcu(entry, &dev->pools) {
   424			struct dev_cgroup_pool_state *pool =
   425				container_of(entry, typeof(*pool), dev_node);
   426	
   427			list_del_rcu(&pool->css_node);
   428		}
   429	
   430		/*
   431		 * Ensure any RCU based lookups fail. Additionally,
   432		 * no new pools should be added to the dead device
   433		 * by get_cg_pool_unlocked.
   434		 */
   435		dev->unregistered = true;
   436		spin_unlock(&devcg_lock);
   437	
   438		kref_put(&dev->ref, devcg_free_device);
   439	}
   440	EXPORT_SYMBOL_GPL(dev_cgroup_unregister_device);
   441	

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