Re: [PATCH v9 5/6] vduse: add vq group asid support

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

Hi Eugenio,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.18-rc5 next-20251113]
[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/Eugenio-P-rez/vduse-add-v1-API-definition/20251113-200303
base:   linus/master
patch link:    https://lore.kernel.org/r/20251113115558.1277981-6-eperezma%40redhat.com
patch subject: [PATCH v9 5/6] vduse: add vq group asid support
config: i386-randconfig-062-20251114 (https://download.01.org/0day-ci/archive/20251114/202511141421.cUqVScv2-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251114/202511141421.cUqVScv2-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/202511141421.cUqVScv2-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/vdpa/vdpa_user/vduse_dev.c:462:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:462:9: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:462:9: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:919:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:919:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:919:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:938:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:938:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:938:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:959:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:959:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:959:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:980:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:980:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:980:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:1001:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:1001:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:1001:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:1025:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:1025:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:1025:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:1044:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:1044:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:1044:14: sparse:    struct vduse_as *
   drivers/vdpa/vdpa_user/vduse_dev.c:1071:14: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/vdpa/vdpa_user/vduse_dev.c:1071:14: sparse:    struct vduse_as [noderef] __rcu *
   drivers/vdpa/vdpa_user/vduse_dev.c:1071:14: sparse:    struct vduse_as *
>> drivers/vdpa/vdpa_user/vduse_dev.c:1074:23: sparse: sparse: dereference of noderef expression

vim +462 drivers/vdpa/vdpa_user/vduse_dev.c

   452	
   453	/* Force set the asid to a vq group without a message to the VDUSE device */
   454	static void vduse_set_group_asid_nomsg(struct vduse_dev *dev,
   455					       unsigned int group, unsigned int asid)
   456	{
   457		/*
   458		 * Two concurrent updates to this pointer are valid as they cannot
   459		 * point to an invalid region.  It is ok for them to race as long as
   460		 * the readers see a consistent state through RCU.
   461		 */
 > 462		rcu_assign_pointer(dev->groups[group].as, &dev->as[asid]);
   463	}
   464	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki