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Date:   Tue, 19 Mar 2019 16:37:36 +0000
Message-ID: <86imwezupb.wl-marc.zyngier@arm.com>
From:   Marc Zyngier <marc.zyngier@arm.com>
To:     Masahiro Yamada <yamada.masahiro@socionext.com>
Cc:     linux-arm-kernel@lists.infradead.org,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        linux-kernel@vger.kernel.org, Yufen Wang <wangyufen@huawei.com>,
        Russell King <linux@armlinux.org.uk>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] ARM: fix out-of-bound access to ipi_types[]
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References: <1553010745-26585-1-git-send-email-yamada.masahiro@socionext.com>
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On Tue, 19 Mar 2019 15:52:25 +0000,
Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
> 
> Since commit e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a
> "non-secure" SGI"), IPI_CPU_BACKTRACE is assigned to SGI7.
> 
> raise_nmi() passes IPI_CPU_BACKTRACE (=7) into smp_cross_call(),
> but it is above the array bound of ipi_types[].
> 
> Increase NR_IPI, and add the entry to ipi_types[].
> 
> This fixes the following GCC warning:
> 
>   CC      arch/arm/kernel/smp.o
> arch/arm/kernel/smp.c: In function 'raise_nmi':
> arch/arm/kernel/smp.c:522:2: warning: array subscript 7 is above array bounds of 'const char *[7]' [-Warray-bounds]
>   trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---

+Arnd.

A fix for this has been around since 2016:

http://lists.infradead.org/pipermail/linux-arm-kernel/2016-February/409393.html

and reposted several times since. I don't know why it hasn't been
picked up.

	M.

-- 
Jazz is not dead, it just smell funny.