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From: Nick Desaulniers <ndesaulniers@google.com>
To: Kees Cook <keescook@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Joe Perches <joe@perches.com>, Andy Whitcroft <apw@canonical.com>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>,
	drbd-dev@lists.linbit.com, linux-block@vger.kernel.org,
	b43-dev@lists.infradead.org,
	Network Development <netdev@vger.kernel.org>,
	Linux Doc Mailing List <linux-doc@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	linux-ide@vger.kernel.org, linux-clk@vger.kernel.org,
	linux-spi@vger.kernel.org,
	Linux Memory Management List <linux-mm@kvack.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH v2 10/16] KVM: PPC: Book3S PR: Remove uninitialized_var() usage
Date: Mon, 22 Jun 2020 10:22:53 -0700	[thread overview]
Message-ID: <CAKwvOd=N3HQNZfKMQ7eZWdawwNn13=YNNgMO0WAng2ERYX4Juw@mail.gmail.com> (raw)
In-Reply-To: <20200620033007.1444705-11-keescook@chromium.org>

On Fri, Jun 19, 2020 at 8:30 PM Kees Cook <keescook@chromium.org> wrote:
>
> Using uninitialized_var() is dangerous as it papers over real bugs[1]
> (or can in the future), and suppresses unrelated compiler warnings (e.g.
> "unused variable"). If the compiler thinks it is uninitialized, either
> simply initialize the variable or make compiler changes. As a precursor
> to removing[2] this[3] macro[4], just remove this variable since it was
> actually unused:
>
> arch/powerpc/kvm/book3s_pr.c:1832:16: warning: unused variable 'vrsave' [-Wunused-variable]
>         unsigned long vrsave;
>                       ^
>
> [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
> [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
> [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
> [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/
>
> Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
> Fixes: f05ed4d56e9c ("KVM: PPC: Split out code from book3s.c into book3s_pr.c")
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  arch/powerpc/kvm/book3s_pr.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
> index ef54f917bdaf..ed12dfbf9bb5 100644
> --- a/arch/powerpc/kvm/book3s_pr.c
> +++ b/arch/powerpc/kvm/book3s_pr.c
> @@ -1828,9 +1828,6 @@ static int kvmppc_vcpu_run_pr(struct kvm_vcpu *vcpu)
>  {
>         struct kvm_run *run = vcpu->run;
>         int ret;
> -#ifdef CONFIG_ALTIVEC
> -       unsigned long uninitialized_var(vrsave);
> -#endif
>
>         /* Check if we can run the vcpu at all */
>         if (!vcpu->arch.sane) {
> --

-- 
Thanks,
~Nick Desaulniers

  reply	other threads:[~2020-06-22 17:23 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-20  3:29 [PATCH v2 00/16] Remove uninitialized_var() macro Kees Cook
2020-06-20  3:29 ` [PATCH v2 01/16] docs: deprecated.rst: Add uninitialized_var() Kees Cook
2020-06-22 16:59   ` Nick Desaulniers
2020-06-20  3:29 ` [PATCH v2 02/16] x86/mm/numa: Remove uninitialized_var() usage Kees Cook
2020-06-20  3:29 ` [PATCH v2 03/16] drbd: " Kees Cook
2020-06-20  3:29 ` [PATCH v2 04/16] b43: " Kees Cook
2020-06-22 17:04   ` Nick Desaulniers
2020-06-22 21:04     ` Kees Cook
2020-06-23 18:29       ` Nick Desaulniers
2020-07-15 10:37   ` Kalle Valo
2020-06-20  3:29 ` [PATCH v2 05/16] rtlwifi: rtl8192cu: " Kees Cook
2020-06-20  3:29 ` [PATCH v2 06/16] ide: " Kees Cook
2020-06-20  3:29 ` [PATCH v2 07/16] clk: st: " Kees Cook
2020-06-22  9:03   ` Stephen Boyd
2020-06-20  3:29 ` [PATCH v2 08/16] spi: davinci: " Kees Cook
2020-07-01 20:39   ` Mark Brown
2020-07-02 15:21     ` Kees Cook
2020-07-02 15:23       ` Mark Brown
2020-07-02 15:42         ` Kees Cook
2020-07-02 16:23           ` Joe Perches
2020-06-20  3:30 ` [PATCH v2 09/16] clk: spear: " Kees Cook
2020-06-22  9:03   ` Stephen Boyd
2020-06-20  3:30 ` [PATCH v2 10/16] KVM: PPC: Book3S PR: " Kees Cook
2020-06-22 17:22   ` Nick Desaulniers [this message]
2020-06-20  3:30 ` [PATCH v2 11/16] media: sur40: " Kees Cook
2020-06-22 18:39   ` Nick Desaulniers
2020-06-20  3:30 ` [PATCH v2 12/16] f2fs: Eliminate usage of uninitialized_var() macro Kees Cook
2020-06-20  3:30 ` [PATCH v2 14/16] checkpatch: Remove awareness " Kees Cook
2020-06-20  3:30 ` [PATCH v2 16/16] compiler: Remove " Kees Cook
2020-06-20  3:30 ` [PATCH v2 13/16] mm/debug_vm_pgtable: Remove uninitialized_var() usage Kees Cook
2020-06-22 17:27   ` Nick Desaulniers
2020-06-20  7:03 ` [PATCH v2 00/16] Remove uninitialized_var() macro Sedat Dilek
2020-06-20 15:57   ` Kees Cook
2020-06-22  9:07     ` Sedat Dilek

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