From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH] ARM: kernel: fix nr_cpu_ids check in DT logical map init Date: Thu, 22 Nov 2012 12:08:43 +0000 Message-ID: <20121122120843.GA16972@e102568-lin.cambridge.arm.com> References: <1353516176-12929-1-git-send-email-lorenzo.pieralisi@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1353516176-12929-1-git-send-email-lorenzo.pieralisi@arm.com> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: "linux@arm.linux.org.uk" Cc: "devicetree-discuss@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org Hi Russell, On Wed, Nov 21, 2012 at 04:42:56PM +0000, Lorenzo Pieralisi wrote: > If a kernel is configured with a DT containing more /cpu nodes than > nr_cpu_ids, the number of cpus must be capped in the DT parsing > code. Current code carries out the check, but fails to cap the > value and the check is executed after the cpu logical index is used, > which can lead to memory corruption due to index overflow. > > This patch refactors the check against nr_cpu_ids and move it before > any computed index is used in the parsing code. > > Signed-off-by: Lorenzo Pieralisi > Reported-by: Mark Rutland > --- > Russell, > > while refactoring the DT loop over nodes, I unfortunately missed this niggle > in the parsing loop that Mark reported. Here is the fix, sorry for the > additional commit, if it is ok for you I will add it to your patch system. > > Apologies and thanks, > Lorenzo > > arch/arm/kernel/devtree.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > index aaf9add..70f1bde 100644 > --- a/arch/arm/kernel/devtree.c > +++ b/arch/arm/kernel/devtree.c > @@ -139,10 +139,14 @@ void __init arm_dt_init_cpu_maps(void) > i = cpuidx++; > } > > - tmp_map[i] = hwid; > - > - if (cpuidx > nr_cpu_ids) > + if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than " > + "max cores %u, capping them\n", > + cpuidx, nr_cpu_ids)) { > + cpuidx = nr_cpu_ids; > break; > + } > + > + tmp_map[i] = hwid; > } > > if (WARN(!bootcpu_valid, "DT missing boot CPU MPIDR[23:0], " If it looks fine to you, can I queue this simple fix in your patch system please ? Thanks and apologies for the extra commit, Lorenzo