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

From: Marc Zyngier <maz@kernel.org>
To: Kalesh Singh <kaleshsingh@google.com>, kernel test robot <lkp@intel.com>
Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org, will@kernel.org,
	qperret@google.com, tabba@google.com, surenb@google.com,
	kernel-team@android.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Joey Gouly <joey.gouly@arm.com>,
	Peter Collingbourne <pcc@google.com>,
	Andrew Scull <ascull@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v2 6/9] KVM: arm64: Detect and handle hypervisor stack overflows
Date: Wed, 23 Feb 2022 09:16:59 +0000	[thread overview]
Message-ID: <875yp63ptg.wl-maz@kernel.org> (raw)
In-Reply-To: <202202231727.L621fVgD-lkp@intel.com>

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.

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