tree: https://github.com/dsahern/linux nexthops/del-group-03 head: b8c06bc47e0a04603de20861b8d5f7291ff0bc12 commit: 063512a047f24cd25298dbb37ae1247a407dbdde [4/7] ipv4: Refactor nhc evaluation in fib_table_lookup :::::: branch date: 19 hours ago :::::: commit date: 20 hours ago config: x86_64-defconfig (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce (this is a W=1 build): git checkout 063512a047f24cd25298dbb37ae1247a407dbdde # save the attached .config to linux build tree make ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; New smatch warnings: net/ipv4/fib_trie.c:1575 fib_table_lookup() error: uninitialized symbol 'nhsel'. # https://github.com/dsahern/linux/commit/063512a047f24cd25298dbb37ae1247a4... git remote add dsahern-linux https://github.com/dsahern/linux git remote update dsahern-linux git checkout 063512a047f24cd25298dbb37ae1247a407dbdde vim +/nhsel +1575 net/ipv4/fib_trie.c 19baf839ff4a8d Robert Olsson 2005-06-21 1519 found: 71e8b67d0fdd2f Alexander Duyck 2015-03-04 1520 /* this line carries forward the xor from earlier in the function */ 71e8b67d0fdd2f Alexander Duyck 2015-03-04 1521 index = key ^ n->key; 71e8b67d0fdd2f Alexander Duyck 2015-03-04 1522 9f9e636d4f89f7 Alexander Duyck 2014-12-31 1523 /* Step 3: Process the leaf, if that fails fall back to backtracing */ 79e5ad2ceb0067 Alexander Duyck 2015-02-25 1524 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) { 345e9b54268ae0 Alexander Duyck 2014-12-31 1525 struct fib_info *fi = fa->fa_info; 063512a047f24c David Ahern 2020-05-21 1526 struct fib_nh_common *nhc; 345e9b54268ae0 Alexander Duyck 2014-12-31 1527 int nhsel, err; ^^^^^ 345e9b54268ae0 Alexander Duyck 2014-12-31 1528 a5829f536b3d11 Alexander Duyck 2016-01-28 1529 if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) { a5829f536b3d11 Alexander Duyck 2016-01-28 1530 if (index >= (1ul << fa->fa_slen)) 9b6ebad5c3a152 Alexander Duyck 2015-02-25 1531 continue; a5829f536b3d11 Alexander Duyck 2016-01-28 1532 } 345e9b54268ae0 Alexander Duyck 2014-12-31 1533 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 345e9b54268ae0 Alexander Duyck 2014-12-31 1534 continue; 345e9b54268ae0 Alexander Duyck 2014-12-31 1535 if (fi->fib_dead) 345e9b54268ae0 Alexander Duyck 2014-12-31 1536 continue; 345e9b54268ae0 Alexander Duyck 2014-12-31 1537 if (fa->fa_info->fib_scope < flp->flowi4_scope) 345e9b54268ae0 Alexander Duyck 2014-12-31 1538 continue; 345e9b54268ae0 Alexander Duyck 2014-12-31 1539 fib_alias_accessed(fa); 345e9b54268ae0 Alexander Duyck 2014-12-31 1540 err = fib_props[fa->fa_type].error; 345e9b54268ae0 Alexander Duyck 2014-12-31 1541 if (unlikely(err < 0)) { 4c7e8084fd467d David Ahern 2019-06-03 1542 out_reject: 345e9b54268ae0 Alexander Duyck 2014-12-31 1543 #ifdef CONFIG_IP_FIB_TRIE_STATS 345e9b54268ae0 Alexander Duyck 2014-12-31 1544 this_cpu_inc(stats->semantic_match_passed); 345e9b54268ae0 Alexander Duyck 2014-12-31 1545 #endif 9f323973c915d4 David Ahern 2018-05-23 1546 trace_fib_table_lookup(tb->tb_id, flp, NULL, err); 345e9b54268ae0 Alexander Duyck 2014-12-31 1547 return err; 345e9b54268ae0 Alexander Duyck 2014-12-31 1548 } 345e9b54268ae0 Alexander Duyck 2014-12-31 1549 if (fi->fib_flags & RTNH_F_DEAD) 345e9b54268ae0 Alexander Duyck 2014-12-31 1550 continue; 4c7e8084fd467d David Ahern 2019-06-03 1551 063512a047f24c David Ahern 2020-05-21 1552 if (unlikely(fi->nh)) { 063512a047f24c David Ahern 2020-05-21 1553 if (nexthop_is_blackhole(fi->nh)) { 4c7e8084fd467d David Ahern 2019-06-03 1554 err = fib_props[RTN_BLACKHOLE].error; 4c7e8084fd467d David Ahern 2019-06-03 1555 goto out_reject; 4c7e8084fd467d David Ahern 2019-06-03 1556 } 4c7e8084fd467d David Ahern 2019-06-03 1557 063512a047f24c David Ahern 2020-05-21 1558 nhc = nexthop_get_nhc_lookup(fi->nh, fib_flags, flp); 063512a047f24c David Ahern 2020-05-21 1559 if (nhc) 063512a047f24c David Ahern 2020-05-21 1560 goto set_result; ^^^^^^^^^^^^^^^ goto 063512a047f24c David Ahern 2020-05-21 1561 goto miss; 063512a047f24c David Ahern 2020-05-21 1562 } 063512a047f24c David Ahern 2020-05-21 1563 5481d73f81549e David Ahern 2019-06-03 1564 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 063512a047f24c David Ahern 2020-05-21 1565 nhc = fib_info_nhc(fi, nhsel); 345e9b54268ae0 Alexander Duyck 2014-12-31 1566 063512a047f24c David Ahern 2020-05-21 1567 if (!fib_lookup_good_nhc(nhc, fib_flags, flp)) 345e9b54268ae0 Alexander Duyck 2014-12-31 1568 continue; 063512a047f24c David Ahern 2020-05-21 1569 set_result: 345e9b54268ae0 Alexander Duyck 2014-12-31 1570 if (!(fib_flags & FIB_LOOKUP_NOREF)) 0029c0deb590bc Reshetova, Elena 2017-07-04 1571 refcount_inc(&fi->fib_clntref); 345e9b54268ae0 Alexander Duyck 2014-12-31 1572 6ffd903415320d David Ahern 2017-05-25 1573 res->prefix = htonl(n->key); 9b6ebad5c3a152 Alexander Duyck 2015-02-25 1574 res->prefixlen = KEYLENGTH - fa->fa_slen; 345e9b54268ae0 Alexander Duyck 2014-12-31 @1575 res->nh_sel = nhsel; ^^^^^^^^^^^^^^^^^^^ Uninitialized. eba618abacade7 David Ahern 2019-04-02 1576 res->nhc = nhc; 345e9b54268ae0 Alexander Duyck 2014-12-31 1577 res->type = fa->fa_type; 345e9b54268ae0 Alexander Duyck 2014-12-31 1578 res->scope = fi->fib_scope; 345e9b54268ae0 Alexander Duyck 2014-12-31 1579 res->fi = fi; 345e9b54268ae0 Alexander Duyck 2014-12-31 1580 res->table = tb; 79e5ad2ceb0067 Alexander Duyck 2015-02-25 1581 res->fa_head = &n->leaf; 345e9b54268ae0 Alexander Duyck 2014-12-31 1582 #ifdef CONFIG_IP_FIB_TRIE_STATS 345e9b54268ae0 Alexander Duyck 2014-12-31 1583 this_cpu_inc(stats->semantic_match_passed); 345e9b54268ae0 Alexander Duyck 2014-12-31 1584 #endif eba618abacade7 David Ahern 2019-04-02 1585 trace_fib_table_lookup(tb->tb_id, flp, nhc, err); f6d3c19274c74f David Ahern 2015-08-28 1586 345e9b54268ae0 Alexander Duyck 2014-12-31 1587 return err; 345e9b54268ae0 Alexander Duyck 2014-12-31 1588 } 345e9b54268ae0 Alexander Duyck 2014-12-31 1589 } 063512a047f24c David Ahern 2020-05-21 1590 miss: 345e9b54268ae0 Alexander Duyck 2014-12-31 1591 #ifdef CONFIG_IP_FIB_TRIE_STATS 345e9b54268ae0 Alexander Duyck 2014-12-31 1592 this_cpu_inc(stats->semantic_match_miss); 345e9b54268ae0 Alexander Duyck 2014-12-31 1593 #endif 9f9e636d4f89f7 Alexander Duyck 2014-12-31 1594 goto backtrace; 19baf839ff4a8d Robert Olsson 2005-06-21 1595 } 6fc01438a94702 Florian Westphal 2011-08-25 1596 EXPORT_SYMBOL_GPL(fib_table_lookup); --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org