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

From: Philip Li
Date: Wed Feb 23 2022 - 07:36:47 EST


On Wed, Feb 23, 2022 at 09:16:59AM +0000, Marc Zyngier wrote:
> On Wed, 23 Feb 2022 09:05:18 +0000,
> kernel test robot <lkp@xxxxxxxxx> 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@xxxxxxxxx/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@xxxxxxxxx>
> >
> > 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.

Hi Kalesh, sorry there're some irrelevant issues mixed in the report,
kindly ignore them. And the valuable ones are the new ones that
prefixed by >>, as the below one in original report.

>> arch/arm64/kvm/hyp/nvhe/switch.c:372:17: warning: no previous prototype for function 'hyp_panic_bad_stack' [-Wmissing-prototypes]
void __noreturn hyp_panic_bad_stack(void)
^
Thanks

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