linux-kernel - Re: [PATCH 6.1.y] KVM: arm64: sys_regs: disable -Wuninitialized-const-pointer warning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20250806222557.GA1654483@ax162>
Date: Wed, 6 Aug 2025 15:25:57 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Justin Stitt <justinstitt@...gle.com>
Cc: Marc Zyngier <maz@...nel.org>, James Morse <james.morse@....com>,
	Alexandru Elisei <alexandru.elisei@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, Tom Rix <trix@...hat.com>,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
	stable@...r.kernel.org
Subject: Re: [PATCH 6.1.y] KVM: arm64: sys_regs: disable
 -Wuninitialized-const-pointer warning

On Mon, Jul 28, 2025 at 02:07:36PM -0700, Justin Stitt wrote:
> A new warning in Clang 22 [1] complains that @clidr passed to
> get_clidr_el1() is an uninitialized const pointer. get_clidr_el1()
> doesn't really care since it casts away the const-ness anyways -- it is
> a false positive.
> 
> |  ../arch/arm64/kvm/sys_regs.c:2978:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer]
> |   2978 |         get_clidr_el1(NULL, &clidr); /* Ugly... */
> |        |                              ^~~~~
> 
> Disable this warning for sys_regs.o with an iron fist as it doesn't make
> sense to waste maintainer's time or potentially break builds by
> backporting large changelists from 6.2+.
> 
> This patch isn't needed for anything past 6.1 as this code section was
> reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache
> configuration").
> 
> Cc: stable@...r.kernel.org
> Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling")
> Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d441f19b319e [1]
> Signed-off-by: Justin Stitt <justinstitt@...gle.com>
> ---

Yes, I think this is an appropriate way to address this for stable.

Reviewed-by: Nathan Chancellor <nathan@...nel.org>

> ---
>  arch/arm64/kvm/Makefile | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
> index 5e33c2d4645a..5fdb5331bfad 100644
> --- a/arch/arm64/kvm/Makefile
> +++ b/arch/arm64/kvm/Makefile
> @@ -24,6 +24,9 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
>  
>  kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
>  
> +# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning
> +CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer)
> +
>  always-y := hyp_constants.h hyp-constants.s
>  
>  define rule_gen_hyp_constants
> 
> ---
> base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476
> change-id: 20250728-stable-disable-unit-ptr-warn-281fee82539c
> 
> Best regards,
> --
> Justin Stitt <justinstitt@...gle.com>
>