Hi Florian, I love your patch! Yet something to improve: [auto build test ERROR on nf/master] url: https://github.com/0day-ci/linux/commits/Florian-Westphal/netfilter-nat-f... base: https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf.git master config: arm-randconfig-r005-20211216 (https://download.01.org/0day-ci/archive/20211217/202112170757.knetsZWh-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project dd245bab9fbb364faa1581e4f92ba3119a872fba) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://github.com/0day-ci/linux/commit/cc216934b951862fcd3ea10c9bef2eecd... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Florian-Westphal/netfilter-nat-force-port-remap-to-prevent-shadowing-well-known-ports/20211216-232930 git checkout cc216934b951862fcd3ea10c9bef2eecd84d8e6f # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash net/netfilter/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): !ct->local_origin) ~~ ^ 1 error generated. vim +550 net/netfilter/nf_nat_core.c 528 529 /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING, 530 * we change the source to map into the range. For NF_INET_PRE_ROUTING 531 * and NF_INET_LOCAL_OUT, we change the destination to map into the 532 * range. It might not be possible to get a unique tuple, but we try. 533 * At worst (or if we race), we will end up with a final duplicate in 534 * __nf_conntrack_confirm and drop the packet. */ 535 static void 536 get_unique_tuple(struct nf_conntrack_tuple *tuple, 537 const struct nf_conntrack_tuple *orig_tuple, 538 const struct nf_nat_range2 *range, 539 struct nf_conn *ct, 540 enum nf_nat_manip_type maniptype) 541 { 542 bool random_port = range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL; 543 const struct nf_conntrack_zone *zone; 544 struct net *net = nf_ct_net(ct); 545 546 zone = nf_ct_zone(ct); 547 548 if (maniptype == NF_NAT_MANIP_SRC && 549 !random_port && 551 random_port = tuple_force_port_remap(orig_tuple); 552 553 /* 1) If this srcip/proto/src-proto-part is currently mapped, 554 * and that same mapping gives a unique tuple within the given 555 * range, use that. 556 * 557 * This is only required for source (ie. NAT/masq) mappings. 558 * So far, we don't do local source mappings, so multiple 559 * manips not an issue. 560 */ 561 if (maniptype == NF_NAT_MANIP_SRC && !random_port) { 562 /* try the original tuple first */ 563 if (in_range(orig_tuple, range)) { 564 if (!nf_nat_used_tuple(orig_tuple, ct)) { 565 *tuple = *orig_tuple; 566 return; 567 } 568 } else if (find_appropriate_src(net, zone, 569 orig_tuple, tuple, range)) { 570 pr_debug("get_unique_tuple: Found current src map\n"); 571 if (!nf_nat_used_tuple(tuple, ct)) 572 return; 573 } 574 } 575 576 /* 2) Select the least-used IP/proto combination in the given range */ 577 *tuple = *orig_tuple; 578 find_best_ips_proto(zone, tuple, range, ct, maniptype); 579 580 /* 3) The per-protocol part of the manip is made to map into 581 * the range to make a unique tuple. 582 */ 583 584 /* Only bother mapping if it's not already in range and unique */ 585 if (!random_port) { 586 if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { 587 if (!(range->flags & NF_NAT_RANGE_PROTO_OFFSET) && 588 l4proto_in_range(tuple, maniptype, 589 &range->min_proto, 590 &range->max_proto) && 591 (range->min_proto.all == range->max_proto.all || 592 !nf_nat_used_tuple(tuple, ct))) 593 return; 594 } else if (!nf_nat_used_tuple(tuple, ct)) { 595 return; 596 } 597 } 598 599 /* Last chance: get protocol to try to obtain unique tuple. */ 600 nf_nat_l4proto_unique_tuple(tuple, range, maniptype, ct); 601 } 602 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org