kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression

* kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
@ 2021-11-20  1:45 kernel test robot
  0 siblings, 0 replies; 7+ messages in thread
From: kernel test robot @ 2021-11-20  1:45 UTC (permalink / raw)
  To: Toke Høiland-Jørgensen
  Cc: kbuild-all, linux-kernel, Daniel Borkmann

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   a90af8f15bdc9449ee2d24e1d73fa3f7e8633f81
commit: 782347b6bcad07ddb574422e01e22c92e05928c8 xdp: Add proper __rcu annotations to redirect map entries
date:   5 months ago
config: ia64-randconfig-s032-20211116 (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=782347b6bcad07ddb574422e01e22c92e05928c8
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 782347b6bcad07ddb574422e01e22c92e05928c8
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=ia64 SHELL=/bin/bash kernel/bpf/ lib/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
   kernel/bpf/devmap.c:561:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
   kernel/bpf/devmap.c:561:29: sparse:     expected struct bpf_dtab_netdev *dst
   kernel/bpf/devmap.c:561:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
   kernel/bpf/devmap.c:657:29: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct bpf_dtab_netdev *dst @@     got struct bpf_dtab_netdev [noderef] __rcu * @@
   kernel/bpf/devmap.c:657:29: sparse:     expected struct bpf_dtab_netdev *dst
   kernel/bpf/devmap.c:657:29: sparse:     got struct bpf_dtab_netdev [noderef] __rcu *
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression
>> kernel/bpf/devmap.c:1030:40: sparse: sparse: cast removes address space '__rcu' of expression

vim +/__rcu +1030 kernel/bpf/devmap.c

   990	
   991	static int dev_map_notification(struct notifier_block *notifier,
   992					ulong event, void *ptr)
   993	{
   994		struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
   995		struct bpf_dtab *dtab;
   996		int i, cpu;
   997	
   998		switch (event) {
   999		case NETDEV_REGISTER:
  1000			if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
  1001				break;
  1002	
  1003			/* will be freed in free_netdev() */
  1004			netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
  1005			if (!netdev->xdp_bulkq)
  1006				return NOTIFY_BAD;
  1007	
  1008			for_each_possible_cpu(cpu)
  1009				per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
  1010			break;
  1011		case NETDEV_UNREGISTER:
  1012			/* This rcu_read_lock/unlock pair is needed because
  1013			 * dev_map_list is an RCU list AND to ensure a delete
  1014			 * operation does not free a netdev_map entry while we
  1015			 * are comparing it against the netdev being unregistered.
  1016			 */
  1017			rcu_read_lock();
  1018			list_for_each_entry_rcu(dtab, &dev_map_list, list) {
  1019				if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
  1020					dev_map_hash_remove_netdev(dtab, netdev);
  1021					continue;
  1022				}
  1023	
  1024				for (i = 0; i < dtab->map.max_entries; i++) {
  1025					struct bpf_dtab_netdev *dev, *odev;
  1026	
  1027					dev = rcu_dereference(dtab->netdev_map[i]);
  1028					if (!dev || netdev != dev->dev)
  1029						continue;
> 1030					odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
  1031					if (dev == odev)
  1032						call_rcu(&dev->rcu,
  1033							 __dev_map_entry_free);
  1034				}
  1035			}
  1036			rcu_read_unlock();
  1037			break;
  1038		default:
  1039			break;
  1040		}
  1041		return NOTIFY_OK;
  1042	}
  1043	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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