tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 8119c4332d253660e0a6b8748fe0749961cfbc97 commit: 868fd970e187d39c586565c875837e530c6f7e1b staging: wfx: improve robustness of wfx_get_hw_rate() date: 7 days ago config: powerpc64-randconfig-r001-20201016 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 5fbab4025eb57b12f2842ab188ff07a110708e1d) 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 powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 868fd970e187d39c586565c875837e530c6f7e1b # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 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 >>): if (rate->idx >= band->n_bitrates) { ^~~~ include/linux/compiler.h:56:47: note: expanded from macro 'if' #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) ^~~~ include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var' #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) ^~~~ drivers/staging/wfx/data_tx.c:23:39: note: initialize the variable 'band' to silence this warning struct ieee80211_supported_band *band; ^ = NULL 1 warning generated. vim +/band +34 drivers/staging/wfx/data_tx.c 19 20 static int wfx_get_hw_rate(struct wfx_dev *wdev, 21 const struct ieee80211_tx_rate *rate) 22 { 23 struct ieee80211_supported_band *band; 24 25 if (rate->idx < 0) 26 return -1; 27 if (rate->flags & IEEE80211_TX_RC_MCS) { 28 if (rate->idx > 7) { 29 WARN(1, "wrong rate->idx value: %d", rate->idx); 30 return -1; 31 } 32 return rate->idx + 14; 33 } 35 WARN(1, "wrong rate->idx value: %d", rate->idx); 36 return -1; 37 } 38 // WFx only support 2GHz, else band information should be retrieved 39 // from ieee80211_tx_info 40 band = wdev->hw->wiphy->bands[NL80211_BAND_2GHZ]; 41 return band->bitrates[rate->idx].hw_value; 42 } 43 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org