Re: [PATCH] ARM: vexpress/spc: Avoid negative array index when !SMP

From: Sudeep Holla <sudeep.holla@arm.com>
To: Liviu Dudau <liviu.dudau@arm.com>
Cc: Kees Cook <keescook@chromium.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Russell King <linux@armlinux.org.uk>,
	Sudeep Holla <sudeep.holla@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] ARM: vexpress/spc: Avoid negative array index when !SMP
Date: Fri, 1 Apr 2022 11:11:47 +0100	[thread overview]
Message-ID: <20220401101147.xtweqtftmtwa3txk@bogus> (raw)
In-Reply-To: <YkbFvYRkcXgo3mpK@e110455-lin.cambridge.arm.com>

On Fri, Apr 01, 2022 at 10:28:29AM +0100, Liviu Dudau wrote:
> On Thu, Mar 31, 2022 at 12:04:43PM -0700, Kees Cook wrote:
> > When building multi_v7_defconfig+CONFIG_SMP=n, -Warray-bounds exposes
> > a couple negative array index accesses:
> > 
> > arch/arm/mach-vexpress/spc.c: In function 've_spc_clk_init':
> > arch/arm/mach-vexpress/spc.c:583:21: warning: array subscript -1 is below array bounds of 'bool[2]' {aka '_Bool[2]'} [-Warray-bounds]
> >   583 |   if (init_opp_table[cluster])
> >       |       ~~~~~~~~~~~~~~^~~~~~~~~
> > arch/arm/mach-vexpress/spc.c:556:7: note: while referencing 'init_opp_table'
> >   556 |  bool init_opp_table[MAX_CLUSTERS] = { false };
> >       |       ^~~~~~~~~~~~~~
> > arch/arm/mach-vexpress/spc.c:592:18: warning: array subscript -1 is below array bounds of 'bool[2]' {aka '_Bool[2]'} [-Warray-bounds]
> >   592 |    init_opp_table[cluster] = true;
> >       |    ~~~~~~~~~~~~~~^~~~~~~~~
> > arch/arm/mach-vexpress/spc.c:556:7: note: while referencing 'init_opp_table'
> >   556 |  bool init_opp_table[MAX_CLUSTERS] = { false };
> >       |       ^~~~~~~~~~~~~~
> > 
> > Skip this logic when built !SMP.
> > 
> > Cc: Liviu Dudau <liviu.dudau@arm.com>
> > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Russell King <linux@armlinux.org.uk>
> > Cc: linux-arm-kernel@lists.infradead.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> 
> Acked-by: Liviu Dudau <liviu.dudau@arm.com>
> 
> Sudeep, can you please take this through your tree for sending it to arm-soc?
>

Sure, I will do that as soon as -rc1 is out.

-- 
Regards,
Sudeep