Hi "Alvin, [FYI, it's a private test report for your RFC patch.] [auto build test WARNING on net-next/master] url: https://github.com/0day-ci/linux/commits/Alvin-ipraga/net-dsa-add-support... base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 9b60ac54ab7cf92af76240cdad549e8fde605eee config: x86_64-randconfig-a014-20210822 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project a83d99c55ebb14532c414066a5aa3bdb65389965) 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 # https://github.com/0day-ci/linux/commit/beb62a71799fa3a99ca2e585290454c60... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Alvin-ipraga/net-dsa-add-support-for-RTL8365MB-VC/20210823-033419 git checkout beb62a71799fa3a99ca2e585290454c60b174cd7 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): u16 out; ^ 1 warning generated. vim +/out +78 net/dsa/tag_rtl8_4.c 71 72 static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb, 73 struct net_device *dev) 74 { 75 struct dsa_port *dp = dsa_slave_to_port(dev); 76 __be16 *p; 77 u8 *tag; 79 80 /* Pad out so that the (stripped) packet is at least 64 bytes long 81 * (including FCS), otherwise the switch will drop the packet. 82 * Then we need an additional 8 bytes for the Realtek tag. 83 */ 84 if (__skb_put_padto(skb, ETH_ZLEN + RTL8_4_TAG_LEN, false)) 85 return NULL; 86 87 skb_push(skb, RTL8_4_TAG_LEN); 88 89 dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN); 90 tag = dsa_etype_header_pos_tx(skb); 91 92 /* Set Realtek EtherType */ 93 p = (__be16 *)tag; 94 *p = htons(RTL8_4_ETHERTYPE); 95 96 /* Set Protocol; zero REASON */ 97 p = (__be16 *)(tag + 2); 98 *p = htons(RTL8_4_PROTOCOL_RTL8365MB << 8); 99 100 /* Zero FID_EN, FID, PRI_EN, PRI, KEEP, LEARN_DIS */ 101 p = (__be16 *)(tag + 4); 102 *p = 0; 103 104 /* Zero ALLOW; set RX (CPU->switch) forwarding port mask */ 105 p = (__be16 *)(tag + 6); 106 out = BIT(dp->index); 107 *p = htons(~(1 << 15) & BIT(dp->index)); 108 109 return skb; 110 } 111 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org