Re: [PATCH v2 6/9] KVM: arm64: Detect and handle hypervisor stack overflows

Marc Zyngier
2022-02-23T09:17:06Z

On Wed, 23 Feb 2022 09:05:18 +0000,
kernel test robot <lkp@intel.com> wrote:
>
> Hi Kalesh,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on cfb92440ee71adcc2105b0890bb01ac3cddb8507]
>
> url: https://github.com/0day-ci/linux/commits/Kalesh-Singh/KVM-arm64-Hypervisor-stack-enhancements/20220223-010522
> base: cfb92440ee71adcc2105b0890bb01ac3cddb8507
> config: arm64-randconfig-r011-20220221 (https://download.01.org/0day-ci/archive/20220223/202202231727.L621fVgD-lkp@intel.com/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
> 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://github.com/0day-ci/linux/commit/7fe99fd40f7c4b2973218045ca5b9c9160524db1
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Kalesh-Singh/KVM-arm64-Hypervisor-stack-enhancements/20220223-010522
> git checkout 7fe99fd40f7c4b2973218045ca5b9c9160524db1
> # save the config file to linux build tree
> mkdir build_dir
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash arch/arm64/
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> include/linux/stddef.h:8:14: note: expanded from macro 'NULL'
> #define NULL ((void *)0)
> ^~~~~~~~~~~
> arch/arm64/kvm/hyp/nvhe/switch.c:200:27: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides]
> [ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
> ^~~~~~~~~~~~~~~~~~~~~
> arch/arm64/kvm/hyp/nvhe/switch.c:196:28: note: previous initialization is here
> [0 ... ESR_ELx_EC_MAX] = NULL,
> ^~~~
> include/linux/stddef.h:8:14: note: expanded from macro 'NULL'
> #define NULL ((void *)0)
> ^~~~~~~~~~~

Kalesh, please ignore this nonsense. There may be things to improve,
but this is *NOT* one of them.

These reports are pretty useless, and just lead people to ignore real
bug reports.

M.

--
Without deviation from the norm, progress is not possible.