tree: git://git.infradead.org/users/hch/misc.git set_fs-sysctl head: 29b9c55afc43fafa2c77b8a7caf8d48ff93234e2 commit: 29b9c55afc43fafa2c77b8a7caf8d48ff93234e2 [6/6] sysctl: pass kernel pointers to ->proc_handler config: mips-lasat_defconfig (attached as .config) compiler: mipsel-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout 29b9c55afc43fafa2c77b8a7caf8d48ff93234e2 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): arch/mips/lasat/sysctl.c: In function 'proc_lasat_ip': 98 | c = p++; | ^ arch/mips/lasat/sysctl.c:125:10: error: dereferencing 'void *' pointer [-Werror] 125 | buffer[len] = '\n'; | ^ 125 | buffer[len] = '\n'; | ^ cc1: all warnings being treated as errors vim +98 arch/mips/lasat/sysctl.c 78 79 #ifdef CONFIG_INET 80 int proc_lasat_ip(struct ctl_table *table, int write, 81 void *buffer, size_t *lenp, loff_t *ppos) 82 { 83 unsigned int ip; 84 char *p, c; 85 int len; 86 char ipbuf[32]; 87 88 if (!table->data || !table->maxlen || !*lenp || 89 (*ppos && !write)) { 90 *lenp = 0; 91 return 0; 92 } 93 94 if (write) { 95 len = 0; 96 p = buffer; 97 while (len < *lenp) { 99 if (c == 0 || c == '\n') 100 break; 101 len++; 102 } 103 if (len >= sizeof(ipbuf)-1) 104 len = sizeof(ipbuf) - 1; 105 memcpy(ipbuf, buffer, len); 106 ipbuf[len] = 0; 107 *ppos += *lenp; 108 /* Now see if we can convert it to a valid IP */ 109 ip = in_aton(ipbuf); 110 *(unsigned int *)(table->data) = ip; 111 lasat_write_eeprom_info(); 112 } else { 113 ip = *(unsigned int *)(table->data); 114 sprintf(ipbuf, "%d.%d.%d.%d", 115 (ip) & 0xff, 116 (ip >> 8) & 0xff, 117 (ip >> 16) & 0xff, 118 (ip >> 24) & 0xff); 119 len = strlen(ipbuf); 120 if (len > *lenp) 121 len = *lenp; 122 if (len) 123 memcpy(buffer, ipbuf, len); 124 if (len < *lenp) { 126 len++; 127 } 128 *lenp = len; 129 *ppos += len; 130 } 131 132 return 0; 133 } 134 #endif 135 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org