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

From: kernel test robot
Date: Fri Nov 19 2021 - 20:47:24 EST

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@xxxxxxxxx>


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@xxxxxxxxxxxx

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