[kbuild-all] drivers/net/dsa/qca8k.c:944 qca8k_parse_port_config() error: testing array offset 'cpu_port_index' after use.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: debe436e77c72fcee804fb867f275e6d31aa999c commit: 5654ec78dd7e64b1e04777b24007344329e6a63b net: dsa: qca8k: rework rgmii delay logic and scan for cpu port 6 config: i386-randconfig-m021-20211025 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; smatch warnings: drivers/net/dsa/qca8k.c:944 qca8k_parse_port_config() error: testing array offset 'cpu_port_index' after use. vim +/cpu_port_index +944 drivers/net/dsa/qca8k.c 6c43809bf1bee7 Ansuel Smith 2021-10-14 934 static int 6c43809bf1bee7 Ansuel Smith 2021-10-14 935 qca8k_parse_port_config(struct qca8k_priv *priv) 6c43809bf1bee7 Ansuel Smith 2021-10-14 936 { 5654ec78dd7e64 Ansuel Smith 2021-10-14 937 int port, cpu_port_index = 0, ret; 6c43809bf1bee7 Ansuel Smith 2021-10-14 938 struct device_node *port_dn; 6c43809bf1bee7 Ansuel Smith 2021-10-14 939 phy_interface_t mode; 6c43809bf1bee7 Ansuel Smith 2021-10-14 940 struct dsa_port *dp; 5654ec78dd7e64 Ansuel Smith 2021-10-14 941 u32 delay; 6c43809bf1bee7 Ansuel Smith 2021-10-14 942 6c43809bf1bee7 Ansuel Smith 2021-10-14 943 /* We have 2 CPU port. Check them */ 5654ec78dd7e64 Ansuel Smith 2021-10-14 @944 for (port = 0; port < QCA8K_NUM_PORTS && cpu_port_index < QCA8K_NUM_CPU_PORTS; port++) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Assume cpu_port_index = QCA8K_NUM_CPU_PORTS - 1; 6c43809bf1bee7 Ansuel Smith 2021-10-14 945 /* Skip every other port */ 6c43809bf1bee7 Ansuel Smith 2021-10-14 946 if (port != 0 && port != 6) 6c43809bf1bee7 Ansuel Smith 2021-10-14 947 continue; 6c43809bf1bee7 Ansuel Smith 2021-10-14 948 6c43809bf1bee7 Ansuel Smith 2021-10-14 949 dp = dsa_to_port(priv->ds, port); 6c43809bf1bee7 Ansuel Smith 2021-10-14 950 port_dn = dp->dn; 5654ec78dd7e64 Ansuel Smith 2021-10-14 951 cpu_port_index++; ^^^^^^^^^^^^^^^^^ cpu_port_index is now out of bounds. 6c43809bf1bee7 Ansuel Smith 2021-10-14 952 6c43809bf1bee7 Ansuel Smith 2021-10-14 953 if (!of_device_is_available(port_dn)) 6c43809bf1bee7 Ansuel Smith 2021-10-14 954 continue; 6c43809bf1bee7 Ansuel Smith 2021-10-14 955 6c43809bf1bee7 Ansuel Smith 2021-10-14 956 ret = of_get_phy_mode(port_dn, &mode); 6c43809bf1bee7 Ansuel Smith 2021-10-14 957 if (ret) 6c43809bf1bee7 Ansuel Smith 2021-10-14 958 continue; 6c43809bf1bee7 Ansuel Smith 2021-10-14 959 5654ec78dd7e64 Ansuel Smith 2021-10-14 960 switch (mode) { 5654ec78dd7e64 Ansuel Smith 2021-10-14 961 case PHY_INTERFACE_MODE_RGMII: 5654ec78dd7e64 Ansuel Smith 2021-10-14 962 case PHY_INTERFACE_MODE_RGMII_ID: 5654ec78dd7e64 Ansuel Smith 2021-10-14 963 case PHY_INTERFACE_MODE_RGMII_TXID: 5654ec78dd7e64 Ansuel Smith 2021-10-14 964 case PHY_INTERFACE_MODE_RGMII_RXID: 5654ec78dd7e64 Ansuel Smith 2021-10-14 965 delay = 0; 5654ec78dd7e64 Ansuel Smith 2021-10-14 966 5654ec78dd7e64 Ansuel Smith 2021-10-14 967 if (!of_property_read_u32(port_dn, "tx-internal-delay-ps", &delay)) 5654ec78dd7e64 Ansuel Smith 2021-10-14 968 /* Switch regs accept value in ns, convert ps to ns */ 5654ec78dd7e64 Ansuel Smith 2021-10-14 969 delay = delay / 1000; 5654ec78dd7e64 Ansuel Smith 2021-10-14 970 else if (mode == PHY_INTERFACE_MODE_RGMII_ID || 5654ec78dd7e64 Ansuel Smith 2021-10-14 971 mode == PHY_INTERFACE_MODE_RGMII_TXID) 5654ec78dd7e64 Ansuel Smith 2021-10-14 972 delay = 1; 5654ec78dd7e64 Ansuel Smith 2021-10-14 973 5654ec78dd7e64 Ansuel Smith 2021-10-14 974 if (delay > QCA8K_MAX_DELAY) { 5654ec78dd7e64 Ansuel Smith 2021-10-14 975 dev_err(priv->dev, "rgmii tx delay is limited to a max value of 3ns, setting to the max value"); 5654ec78dd7e64 Ansuel Smith 2021-10-14 976 delay = 3; 5654ec78dd7e64 Ansuel Smith 2021-10-14 977 } 5654ec78dd7e64 Ansuel Smith 2021-10-14 978 5654ec78dd7e64 Ansuel Smith 2021-10-14 979 priv->rgmii_tx_delay[cpu_port_index] = delay; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Out of bounds 5654ec78dd7e64 Ansuel Smith 2021-10-14 980 5654ec78dd7e64 Ansuel Smith 2021-10-14 981 delay = 0; 5654ec78dd7e64 Ansuel Smith 2021-10-14 982 5654ec78dd7e64 Ansuel Smith 2021-10-14 983 if (!of_property_read_u32(port_dn, "rx-internal-delay-ps", &delay)) 5654ec78dd7e64 Ansuel Smith 2021-10-14 984 /* Switch regs accept value in ns, convert ps to ns */ 5654ec78dd7e64 Ansuel Smith 2021-10-14 985 delay = delay / 1000; 5654ec78dd7e64 Ansuel Smith 2021-10-14 986 else if (mode == PHY_INTERFACE_MODE_RGMII_ID || 5654ec78dd7e64 Ansuel Smith 2021-10-14 987 mode == PHY_INTERFACE_MODE_RGMII_RXID) 5654ec78dd7e64 Ansuel Smith 2021-10-14 988 delay = 2; 5654ec78dd7e64 Ansuel Smith 2021-10-14 989 5654ec78dd7e64 Ansuel Smith 2021-10-14 990 if (delay > QCA8K_MAX_DELAY) { 5654ec78dd7e64 Ansuel Smith 2021-10-14 991 dev_err(priv->dev, "rgmii rx delay is limited to a max value of 3ns, setting to the max value"); 5654ec78dd7e64 Ansuel Smith 2021-10-14 992 delay = 3; 5654ec78dd7e64 Ansuel Smith 2021-10-14 993 } 5654ec78dd7e64 Ansuel Smith 2021-10-14 994 5654ec78dd7e64 Ansuel Smith 2021-10-14 995 priv->rgmii_rx_delay[cpu_port_index] = delay; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Out of bounds 5654ec78dd7e64 Ansuel Smith 2021-10-14 996 5654ec78dd7e64 Ansuel Smith 2021-10-14 997 break; 5654ec78dd7e64 Ansuel Smith 2021-10-14 998 case PHY_INTERFACE_MODE_SGMII: 6c43809bf1bee7 Ansuel Smith 2021-10-14 999 if (of_property_read_bool(port_dn, "qca,sgmii-txclk-falling-edge")) 6c43809bf1bee7 Ansuel Smith 2021-10-14 1000 priv->sgmii_tx_clk_falling_edge = true; 6c43809bf1bee7 Ansuel Smith 2021-10-14 1001 6c43809bf1bee7 Ansuel Smith 2021-10-14 1002 if (of_property_read_bool(port_dn, "qca,sgmii-rxclk-falling-edge")) 6c43809bf1bee7 Ansuel Smith 2021-10-14 1003 priv->sgmii_rx_clk_falling_edge = true; 5654ec78dd7e64 Ansuel Smith 2021-10-14 1004 5654ec78dd7e64 Ansuel Smith 2021-10-14 1005 break; 5654ec78dd7e64 Ansuel Smith 2021-10-14 1006 default: 5654ec78dd7e64 Ansuel Smith 2021-10-14 1007 continue; 6c43809bf1bee7 Ansuel Smith 2021-10-14 1008 } 6c43809bf1bee7 Ansuel Smith 2021-10-14 1009 } 6c43809bf1bee7 Ansuel Smith 2021-10-14 1010 6c43809bf1bee7 Ansuel Smith 2021-10-14 1011 return 0; 6c43809bf1bee7 Ansuel Smith 2021-10-14 1012 } --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org