On Thu, Oct 19, 2023 at 04:07:35AM +0800, kernel test robot wrote:

arch/s390/include/asm/ctlreg.h:129:9: warning: array subscript 0 is outside array bounds of 'struct ctlreg[0]' [-Warray-bounds=]
arch/s390/include/asm/ctlreg.h:80:9: warning: array subscript 0 is outside array bounds of 'struct ctlreg[0]' [-Warray-bounds=]

...

|-- s390-defconfig
|   `-- arch-s390-include-asm-ctlreg.h:warning:array-subscript-is-outside-array-bounds-of-struct-ctlreg

...

s390                                defconfig   gcc  

I'm wondering how this warning can appear in the builds. array-bounds
warnings are explicitly disabled, see init/Kconfig: CC_NO_ARRAY_BOUNDS. And
as expected, if I compile the kernel with gcc, defconfig, and with or
without W=1 the option -Wno-array-bounds is passed to the compiler.

And also as expected I do not see the above warnings.

So something is quite odd here.