[PATCH bpf-next 1/4] kernfs: Add __kernfs_xattr_get for RCU protected access

[kernel test robot]

Hi Song,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Song-Liu/kernfs-Add-__kernfs_xattr_get-for-RCU-protected-access/20250619-074026
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20250618233739.189106-2-song%40kernel.org
patch subject: [PATCH bpf-next 1/4] kernfs: Add __kernfs_xattr_get for RCU protected access
config: m68k-randconfig-r122-20250619 (https://download.01.org/0day-ci/archive/20250619/202506192154.T111naKp-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 8.5.0
reproduce: (https://download.01.org/0day-ci/archive/20250619/202506192154.T111naKp-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506192154.T111naKp-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> fs/kernfs/inode.c:312:17: sparse: sparse: incompatible types in comparison expression (different address spaces):
   fs/kernfs/inode.c:312:17: sparse:    struct kernfs_iattrs [noderef] __rcu *
   fs/kernfs/inode.c:312:17: sparse:    struct kernfs_iattrs *

vim +312 fs/kernfs/inode.c

   304	
   305	int __kernfs_xattr_get(struct kernfs_node *kn, const char *name,
   306			       void *value, size_t size)
   307	{
   308		struct kernfs_iattrs *attrs;
   309	
   310		WARN_ON_ONCE(!rcu_read_lock_held());
   311	
 > 312		attrs = rcu_dereference(kn->iattr);
   313		if (!attrs)
   314			return -ENODATA;
   315	
   316		return simple_xattr_get(&attrs->xattrs, name, value, size);
   317	}
   318	

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