Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756664Ab3IZKgK (ORCPT ); Thu, 26 Sep 2013 06:36:10 -0400 Received: from mail.active-venture.com ([67.228.131.205]:52361 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755999Ab3IZKgJ (ORCPT ); Thu, 26 Sep 2013 06:36:09 -0400 X-Originating-IP: 108.223.40.66 Message-ID: <52440E15.7060002@roeck-us.net> Date: Thu, 26 Sep 2013 03:36:05 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: Henrik Rydberg 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 References: <20130925195628.GA1532@roeck-us.net> <20130925214807.GA3234@polaris.bitmath.org> <20130925220838.GB4184@roeck-us.net> <20130926063453.GA526@polaris.bitmath.org> In-Reply-To: <20130926063453.GA526@polaris.bitmath.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3050 Lines: 90 On 09/25/2013 11:34 PM, Henrik Rydberg wrote: >>>> 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. > There are also ACPI conflicts in each of the bug reports I looked at. Can this play a role, or is that "normal" on apple systems ? Thanks, Guenter > 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) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/