[kbuild-all] net/ipv4/tcp_cong.c:238:22: sparse: sparse: incorrect type in assignment (different address spaces)

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 881007522c8fcc3785c75432dbb149ca1b78e106 commit: e188f3330a13df904d77003846eafd3edf99009d ARC: cmpxchg/xchg: rewrite as macros to make type safe date: 3 months ago config: arc-randconfig-s032-20211103 (attached as .config) compiler: arceb-elf-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... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout e188f3330a13df904d77003846eafd3edf99009d # 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__' ARCH=arc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) net/ipv4/tcp_cong.c:238:24: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct tcp_congestion_ops const [noderef] __rcu *_val_ @@ got struct tcp_congestion_ops *[assigned] ca @@ net/ipv4/tcp_cong.c:238:24: sparse: expected struct tcp_congestion_ops const [noderef] __rcu *_val_ net/ipv4/tcp_cong.c:238:24: sparse: got struct tcp_congestion_ops *[assigned] ca net/ipv4/tcp_cong.c:238:22: sparse: expected struct tcp_congestion_ops const *prev net/ipv4/tcp_cong.c:238:22: sparse: got struct tcp_congestion_ops const [noderef] __rcu *[assigned] _val_ vim +238 net/ipv4/tcp_cong.c 317a76f9a44b43 Stephen Hemminger 2005-06-23 219 317a76f9a44b43 Stephen Hemminger 2005-06-23 220 /* Used by sysctl to change default congestion control */ 6670e152447732 Stephen Hemminger 2017-11-14 221 int tcp_set_default_congestion_control(struct net *net, const char *name) 317a76f9a44b43 Stephen Hemminger 2005-06-23 222 { 317a76f9a44b43 Stephen Hemminger 2005-06-23 223 struct tcp_congestion_ops *ca; 6670e152447732 Stephen Hemminger 2017-11-14 224 const struct tcp_congestion_ops *prev; 6670e152447732 Stephen Hemminger 2017-11-14 225 int ret; 317a76f9a44b43 Stephen Hemminger 2005-06-23 226 6670e152447732 Stephen Hemminger 2017-11-14 227 rcu_read_lock(); 6670e152447732 Stephen Hemminger 2017-11-14 228 ca = tcp_ca_find_autoload(net, name); 6670e152447732 Stephen Hemminger 2017-11-14 229 if (!ca) { 6670e152447732 Stephen Hemminger 2017-11-14 230 ret = -ENOENT; 0baf26b0fcd74b Martin KaFai Lau 2020-01-08 231 } else if (!bpf_try_module_get(ca, ca->owner)) { 6670e152447732 Stephen Hemminger 2017-11-14 232 ret = -EBUSY; 8d432592f30fcc Jonathon Reinhart 2021-05-01 233 } else if (!net_eq(net, &init_net) && 8d432592f30fcc Jonathon Reinhart 2021-05-01 234 !(ca->flags & TCP_CONG_NON_RESTRICTED)) { 8d432592f30fcc Jonathon Reinhart 2021-05-01 235 /* Only init netns can set default to a restricted algorithm */ 8d432592f30fcc Jonathon Reinhart 2021-05-01 236 ret = -EPERM; 6670e152447732 Stephen Hemminger 2017-11-14 237 } else { 6670e152447732 Stephen Hemminger 2017-11-14 @238 prev = xchg(&net->ipv4.tcp_congestion_control, ca); 6670e152447732 Stephen Hemminger 2017-11-14 239 if (prev) 0baf26b0fcd74b Martin KaFai Lau 2020-01-08 240 bpf_module_put(prev, prev->owner); 317a76f9a44b43 Stephen Hemminger 2005-06-23 241 6670e152447732 Stephen Hemminger 2017-11-14 242 ca->flags |= TCP_CONG_NON_RESTRICTED; 317a76f9a44b43 Stephen Hemminger 2005-06-23 243 ret = 0; 317a76f9a44b43 Stephen Hemminger 2005-06-23 244 } 6670e152447732 Stephen Hemminger 2017-11-14 245 rcu_read_unlock(); 317a76f9a44b43 Stephen Hemminger 2005-06-23 246 317a76f9a44b43 Stephen Hemminger 2005-06-23 247 return ret; 317a76f9a44b43 Stephen Hemminger 2005-06-23 248 } 317a76f9a44b43 Stephen Hemminger 2005-06-23 249 :::::: The code at line 238 was first introduced by commit :::::: 6670e152447732ba90626f36dfc015a13fbf150e tcp: Namespace-ify sysctl_tcp_default_congestion_control :::::: TO: Stephen Hemminger <stephen(a)networkplumber.org&gt; :::::: CC: David S. Miller <davem(a)davemloft.net&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org