Hi Stephen,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Stephen-Suryaputra/ipmr-ip6mr-APIs-to-support-adding-more-than-MAXVIFS-MAXMIFS/20210918-064706
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git af54faab84f754ebd42ecdda871f8d71940ae40b
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/a569861a106aab4e715ba5e5ed82db0c20c2ca92
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Stephen-Suryaputra/ipmr-ip6mr-APIs-to-support-adding-more-than-MAXVIFS-MAXMIFS/20210918-064706
        git checkout a569861a106aab4e715ba5e5ed82db0c20c2ca92
        # save the attached .config to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

   In file included from include/linux/mroute.h:10,
                    from net/ipv4/raw.c:51:
>> include/linux/mroute_base.h:141:23: error: 'CONFIG_IP_MROUTE_EXT_MAXVIFS' undeclared here (not in a function)
     141 |    unsigned char ttls[CONFIG_IP_MROUTE_EXT_MAXVIFS];
         |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
   In file included from include/linux/mroute.h:10,
                    from net/ipv4/route.c:83:
>> include/linux/mroute_base.h:141:23: error: 'CONFIG_IP_MROUTE_EXT_MAXVIFS' undeclared here (not in a function)
     141 |    unsigned char ttls[CONFIG_IP_MROUTE_EXT_MAXVIFS];
         |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   net/ipv4/route.c: In function 'ip_rt_send_redirect':
   net/ipv4/route.c:877:6: warning: variable 'log_martians' set but not used [-Wunused-but-set-variable]
     877 |  int log_martians;
         |      ^~~~~~~~~~~~


vim +/CONFIG_IP_MROUTE_EXT_MAXVIFS +141 include/linux/mroute_base.h

   102	
   103	/**
   104	 * struct mr_mfc - common multicast routing entries
   105	 * @mnode: rhashtable list
   106	 * @mfc_parent: source interface (iif)
   107	 * @mfc_flags: entry flags
   108	 * @expires: unresolved entry expire time
   109	 * @unresolved: unresolved cached skbs
   110	 * @last_assert: time of last assert
   111	 * @minvif: minimum VIF id
   112	 * @maxvif: maximum VIF id
   113	 * @bytes: bytes that have passed for this entry
   114	 * @pkt: packets that have passed for this entry
   115	 * @wrong_if: number of wrong source interface hits
   116	 * @lastuse: time of last use of the group (traffic or update)
   117	 * @ttls: OIF TTL threshold array
   118	 * @refcount: reference count for this entry
   119	 * @list: global entry list
   120	 * @rcu: used for entry destruction
   121	 * @free: Operation used for freeing an entry under RCU
   122	 */
   123	struct mr_mfc {
   124		struct rhlist_head mnode;
   125		unsigned short mfc_parent;
   126		int mfc_flags;
   127	
   128		union {
   129			struct {
   130				unsigned long expires;
   131				struct sk_buff_head unresolved;
   132			} unres;
   133			struct {
   134				unsigned long last_assert;
   135				int minvif;
   136				int maxvif;
   137				unsigned long bytes;
   138				unsigned long pkt;
   139				unsigned long wrong_if;
   140				unsigned long lastuse;
 > 141				unsigned char ttls[CONFIG_IP_MROUTE_EXT_MAXVIFS];
   142				refcount_t refcount;
   143			} res;
   144		} mfc_un;
   145		struct list_head list;
   146		struct rcu_head	rcu;
   147		void (*free)(struct rcu_head *head);
   148	};
   149	

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