From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755714Ab3IZGd6 (ORCPT ); Thu, 26 Sep 2013 02:33:58 -0400 Received: from smtprelay-b31.telenor.se ([213.150.131.20]:43587 "EHLO smtprelay-b31.telenor.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751425Ab3IZGd4 (ORCPT ); Thu, 26 Sep 2013 02:33:56 -0400 X-SENDER-IP: [85.230.168.69] X-LISTENER: [smtp.bredband.net] X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AtE/ADzUQ1JV5qhFPGdsb2JhbABbgwfBX4EfFwMBAQEBODWCJQEBBAEnExwTAQ8FCwgDDgMDAQIKJQ8FJQoMDhOIAAq8ehaNcIFLB4MdgQEDl3uGRo5YOoEs X-IronPort-AV: E=Sophos;i="4.90,982,1371074400"; d="scan'208";a="400957054" Date: Thu, 26 Sep 2013 08:34:53 +0200 From: Henrik Rydberg To: Guenter Roeck Cc: Josh Boyer , khali@linux-fr.org, lm-sensors@lm-sensors.org, "Linux-Kernel@Vger. Kernel. Org" , bugzilla@colorremedies.com Subject: Re: applesmc oops in 3.10/3.11 Message-ID: <20130926063453.GA526@polaris.bitmath.org> References: <20130925195628.GA1532@roeck-us.net> <20130925214807.GA3234@polaris.bitmath.org> <20130925220838.GB4184@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130925220838.GB4184@roeck-us.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > This suggests that initialization may be attempted more than once. The key cache > > > is allocated only once, but the number of keys is read for each attempt. > > > > > > No idea if that can happen, but if the number of keys can increase after > > > the first initialization attempt you would have an explanation for the crash. > > > > Good idea, and easy enough to test with the patch below. > > > Should we apply this patch even though it may not solve the specific problem ? Yes, why not - it certainly won't hurt. I am running it right now, so it is at least run-tested. > Again, not sure if the key count can change, but the current code is at the very > least inconsistent, as it keeps reading the key count without updating or > verifying the cache size. Yes - I agree that the error state is far-fetched, but it is hard to see any other logical explanation. There is of course always the possibility that the problem is somewhere else completely. Proper patch attached. Thanks, Henrik --- >>From dedefba9167913c46e1896ce0624e68ffe95d532 Mon Sep 17 00:00:00 2001 From: Henrik Rydberg Date: Thu, 26 Sep 2013 08:33:16 +0200 Subject: [PATCH] hwmon: (applesmc) Check key count before proceeding After reports from Chris and Josh Boyer of a rare crash in applesmc, Guenter pointed at the initialization problem fixed below. The patch has not been verified to fix the crash, but should be applied regardless. Reported-by: Suggested-by: Guenter Roeck Signed-off-by: Henrik Rydberg --- drivers/hwmon/applesmc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) 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) -- 1.8.3.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Rydberg Date: Thu, 26 Sep 2013 06:34:53 +0000 Subject: Re: [lm-sensors] applesmc oops in 3.10/3.11 Message-Id: <20130926063453.GA526@polaris.bitmath.org> List-Id: References: <20130925195628.GA1532@roeck-us.net> <20130925214807.GA3234@polaris.bitmath.org> <20130925220838.GB4184@roeck-us.net> In-Reply-To: <20130925220838.GB4184@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Guenter Roeck Cc: Josh Boyer , khali@linux-fr.org, lm-sensors@lm-sensors.org, "Linux-Kernel@Vger. Kernel. Org" , bugzilla@colorremedies.com > > > This suggests that initialization may be attempted more than once. The key cache > > > is allocated only once, but the number of keys is read for each attempt. > > > > > > No idea if that can happen, but if the number of keys can increase after > > > the first initialization attempt you would have an explanation for the crash. > > > > Good idea, and easy enough to test with the patch below. > > > Should we apply this patch even though it may not solve the specific problem ? Yes, why not - it certainly won't hurt. I am running it right now, so it is at least run-tested. > Again, not sure if the key count can change, but the current code is at the very > least inconsistent, as it keeps reading the key count without updating or > verifying the cache size. Yes - I agree that the error state is far-fetched, but it is hard to see any other logical explanation. There is of course always the possibility that the problem is somewhere else completely. Proper patch attached. Thanks, Henrik --- >From dedefba9167913c46e1896ce0624e68ffe95d532 Mon Sep 17 00:00:00 2001 From: Henrik Rydberg Date: Thu, 26 Sep 2013 08:33:16 +0200 Subject: [PATCH] hwmon: (applesmc) Check key count before proceeding After reports from Chris and Josh Boyer of a rare crash in applesmc, Guenter pointed at the initialization problem fixed below. The patch has not been verified to fix the crash, but should be applied regardless. Reported-by: Suggested-by: Guenter Roeck Signed-off-by: Henrik Rydberg --- drivers/hwmon/applesmc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) 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) -- 1.8.3.4 _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors