From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756503Ab3KXJdb (ORCPT ); Sun, 24 Nov 2013 04:33:31 -0500 Received: from palahniuk.acksyn.org ([5.9.7.26]:50235 "EHLO palahniuk.acksyn.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756417Ab3KXJd1 (ORCPT ); Sun, 24 Nov 2013 04:33:27 -0500 X-Greylist: delayed 560 seconds by postgrey-1.27 at vger.kernel.org; Sun, 24 Nov 2013 04:33:27 EST Date: Sun, 24 Nov 2013 09:23:59 +0000 From: Michele Baldessari To: Henrik Rydberg Cc: , Guenter Roeck , linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org, bugzilla@colorremedies.com Subject: small regression: hwmon: (applesmc) Check key count before proceeding - 5f4513864304672e6ea9eac60583eeac32e679f2 Message-ID: <20131124092359.4241e633@fante.int.rhx> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.22; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Henrik & Guenther, via commit 5f4513864304672e6ea9eac60583eeac32e679f2 the following code was added: diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c index 62c2e32..98814d1 100644 --- a/drivers/hwmon/applesmc.c +++ b/drivers/hwmon/applesmc.c @@ -525,16 +525,25 @@ static int applesmc_init_smcreg_try(void) { struct applesmc_registers *s = &smcreg; bool left_light_sensor, right_light_sensor; + unsigned int count; u8 tmp[1]; int ret; if (s->init_complete) return 0; - ret = read_register_count(&s->key_count); + ret = read_register_count(&count); if (ret) return ret; + if (s->cache && s->key_count != count) { + pr_warn("key count changed from %d to %d\n", + s->key_count, count); + kfree(s->cache); + s->cache = NULL; + } + s->key_count = count; + if (!s->cache) s->cache = kcalloc(s->key_count, sizeof(*s->cache), GFP_KERNEL); if (!s->cache) The issue Chris has seen in Fedora on one MacBookPro4,1 (https://bugzilla.redhat.com/show_bug.cgi?id=1033414) is that this machine returns a huge number from read_register_count() so now we will try to allocate an insane amount of memory and we will barf: [ 8.603053] applesmc: key count changed from 261 to 1392508929 Dmidecode for this box is here: https://bugzilla.redhat.com/attachment.cgi?id=828118 Do we need to special case this specific machine/smc version or should we limit the kcalloc() call to a somewhat sane limit? Other thoughts? Thanks, Michele