Re: drivers/video/backlight/ltv350qv.c:192:12: warning: stack frame size of 13472 bytes in function 'ltv350qv_power'

From: Andrew Morton
Date: Sun Oct 25 2020 - 15:17:14 EST


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()?