On Sun, Oct 25, 2020 at 12:17:08PM -0700, Andrew Morton wrote: > On Mon, 26 Oct 2020 02:15:37 +0800 kernel test robot <lkp@xxxxxxxxx> wrote: > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > head: d76913908102044f14381df865bb74df17a538cb > > commit: cae9dc35ed9ff82a99754e51d57ff6c332e1f7e4 kasan: allow enabling stack tagging for tag-based mode > > date: 3 months ago > > config: arm64-randconfig-r005-20201026 (attached as .config) > > compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 1c8371692dfe8245bc6690ff1262dcced4649d21) > > 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 arm64 cross compiling tool for clang build > > # apt-get install binutils-aarch64-linux-gnu > > # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cae9dc35ed9ff82a99754e51d57ff6c332e1f7e4 > > git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > git fetch --no-tags linus master > > git checkout cae9dc35ed9ff82a99754e51d57ff6c332e1f7e4 > > # save the attached .config to linux build tree > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > > > All warnings (new ones prefixed by >>): > > > > >> drivers/video/backlight/ltv350qv.c:192:12: warning: stack frame size of 13472 bytes in function 'ltv350qv_power' [-Wframe-larger-than=] > > That's a lot of stack. > > > static int ltv350qv_power(struct ltv350qv *lcd, int power) > > ^ > > 1 warning generated. > > > > vim +/ltv350qv_power +192 drivers/video/backlight/ltv350qv.c > > Odd - the code looks pretty normal. It is possible that your compiler > is (crazily) inlining ltv350qv_write_reg()? Certainly could be. Same config compiled with gcc-9 gives ltv350qv_write_reg() a stack usage that is large but not crazy: 768 bytes and dropping to 480 bytes with the sanitizers disabled. With the sanitizers enabled then even the cumulative stack usage of ltv350qv_power() through to ltv350qv_write_reg() is still less than 1k. Daniel.
