From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] ACPI / CPPC: Fix negative array index read in cppc_set_perf Date: Sat, 16 Dec 2017 02:47:30 +0100 Message-ID: <1775451.pdUQMu89xf@aspire.rjw.lan> References: <20171213224541.GA31477@embeddedor.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from cloudserver094114.home.net.pl ([79.96.170.134]:41958 "EHLO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755868AbdLPBsR (ORCPT ); Fri, 15 Dec 2017 20:48:17 -0500 In-Reply-To: <20171213224541.GA31477@embeddedor.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Gustavo A. R. Silva" Cc: Len Brown , George Cherian , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org On Wednesday, December 13, 2017 11:45:41 PM CET Gustavo A. R. Silva wrote: > If pcc_ss_id is less than 0, there is a negative array index read > before verifying pcc_ss_id is not a negative value. > > Fix this by removing the code that triggers this issue. > > Notice that this code is already properly placed after the check > on pcc_ss_id at line 1182: pcc_ss_data = pcc_data[pcc_ss_id]; > > Addresses-Coverity-ID: 1426090 ("Negative array index read") > Fixes: 1ecbd7170d65 ("ACPI / CPPC: Fix KASAN global out of bounds warning") > Signed-off-by: Gustavo A. R. Silva > --- > drivers/acpi/cppc_acpi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index 30e84cc..06ea474 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -1171,7 +1171,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) > struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu); > struct cpc_register_resource *desired_reg; > int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); > - struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id]; > + struct cppc_pcc_data *pcc_ss_data; > int ret = 0; > > if (!cpc_desc || pcc_ss_id < 0) { > I applied a patch from Coling Ian King that did the same thing and was posted eaelier. Thanks, Rafael