Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756631Ab3DOSHr (ORCPT ); Mon, 15 Apr 2013 14:07:47 -0400 Received: from mail-wg0-f46.google.com ([74.125.82.46]:63926 "EHLO mail-wg0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756037Ab3DOSHp (ORCPT ); Mon, 15 Apr 2013 14:07:45 -0400 MIME-Version: 1.0 Reply-To: sedat.dilek@gmail.com In-Reply-To: References: <1923819.6Nb81T2TR8@vostro.rjw.lan> <516C25AE.4050503@intel.com> Date: Mon, 15 Apr 2013 20:07:43 +0200 Message-ID: Subject: Re: linux-next: Tree for Apr 9 [cpufreq: NULL pointer deref] From: Sedat Dilek To: Viresh Kumar Cc: Dirk Brandewie , "Rafael J. Wysocki" , Dirk Brandewie , Stephen Rothwell , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org, Linux PM list , Lists linaro-kernel , Nathan Zimmer Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5163 Lines: 149 On Mon, Apr 15, 2013 at 7:57 PM, Sedat Dilek wrote: > On Mon, Apr 15, 2013 at 7:51 PM, Sedat Dilek wrote: >> On Mon, Apr 15, 2013 at 7:22 PM, Viresh Kumar wrote: >>> On 15 April 2013 21:37, Dirk Brandewie wrote: >>>> If the intel_pstate driver is being used __cpufreq_governor() should NOT be >>>> called intel_pstate does not implement the target() callback. >>>> >>>> Nathan's commit 5800043b2 changed the fence around the call to >>>> __cpufreq_governor() in __cpufreq_remove_dev() here is the relevant hunk. >>> >>> No it isn't. >>> >>>> + if (has_target) >>>> __cpufreq_governor(data, CPUFREQ_GOV_STOP); >>> >>> As it has taken care of this limitation. >>> >>> BUT some of my earlier patches haven't. :( >>> Here is the fix (Sedat please try this and give your tested-by, use the attached >>> patch as gmail might break what i am copying in mail).. >>> >>> Sorry for being late in fixing this issue, i am still down with Tonsil infection >>> and fever.. Today only i got some power to fix it after seeing Dirk's mail. >>> >>> Your tested-by may help me to recover quickly :) >>> >> >> Hehe. >> Me myself and I was today chez-mon-docteur... Let's see the results on Thursday. >> Again, get well soon. >> >> Tested against... >> >> "BROKEN" Linux-Next (next-20130411) with attached patchset (incl. >> your cpufreq-next-fixes). >> >> Test-Case... >> >> CONFIG_X86_INTEL_PSTATE=y >> >> root# echo 0 > /sys/devices/system/cpu/cpu3/online >> >> Tested-by: Sedat Dilek >> >> ...did not test on-reboot-case. >> Reboot is also fine here. >> ( Dirk promised to test as well... ) >> Dirk confirmed your patch works for him. Good! - Sedat - > > Might be interesting as an extra-confirmation: > > root# echo 1 > /sys/devices/system/cpu/cpu3/online > > [ dmesg ] > > [ 556.101961] smpboot: Booting Node 0 Processor 3 APIC 0x3 > [ 556.113158] Disabled fast string operations > [ 556.116621] Intel pstate controlling: cpu 3 > > - Sedat - > >> - Sedat - >> >>> @Rafael: I will probably be down for one more week and so not doing any >>> reviews for now... I do check important mails sent directly to me though. >>> >>> ------------x----------------------x------------------ >>> >>> From: Viresh Kumar >>> Date: Mon, 15 Apr 2013 22:43:57 +0530 >>> Subject: [PATCH] cpufreq: Don't call __cpufreq_governor() for drivers without >>> target() >>> >>> Some cpufreq drivers implement their own governor and so don't need us to call >>> generic governors interface via __cpufreq_governor(). Few recent commits haven't >>> obeyed this law well and we saw some regressions. >>> >>> This patch tries to fix this issue. >>> >>> Signed-off-by: Viresh Kumar >>> --- >>> drivers/cpufreq/cpufreq.c | 18 +++++++++++++----- >>> 1 file changed, 13 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >>> index 3564947..a6f6595 100644 >>> --- a/drivers/cpufreq/cpufreq.c >>> +++ b/drivers/cpufreq/cpufreq.c >>> @@ -858,13 +858,18 @@ static int cpufreq_add_policy_cpu(unsigned int >>> cpu, unsigned int sibling, >>> struct device *dev) >>> { >>> struct cpufreq_policy *policy; >>> - int ret = 0; >>> + int ret = 0, has_target = 0; >>> unsigned long flags; >>> >>> policy = cpufreq_cpu_get(sibling); >>> WARN_ON(!policy); >>> >>> - __cpufreq_governor(policy, CPUFREQ_GOV_STOP); >>> + rcu_read_lock(); >>> + has_target = !!rcu_dereference(cpufreq_driver)->target; >>> + rcu_read_unlock(); >>> + >>> + if (has_target) >>> + __cpufreq_governor(policy, CPUFREQ_GOV_STOP); >>> >>> lock_policy_rwsem_write(sibling); >>> >>> @@ -877,8 +882,10 @@ static int cpufreq_add_policy_cpu(unsigned int >>> cpu, unsigned int sibling, >>> >>> unlock_policy_rwsem_write(sibling); >>> >>> - __cpufreq_governor(policy, CPUFREQ_GOV_START); >>> - __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); >>> + if (has_target) { >>> + __cpufreq_governor(policy, CPUFREQ_GOV_START); >>> + __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); >>> + } >>> >>> ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); >>> if (ret) { >>> @@ -1146,7 +1153,8 @@ static int __cpufreq_remove_dev(struct device >>> *dev, struct subsys_interface *sif >>> >>> /* If cpu is last user of policy, free policy */ >>> if (cpus == 1) { >>> - __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); >>> + if (has_target) >>> + __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); >>> >>> lock_policy_rwsem_read(cpu); >>> kobj = &data->kobj; -- 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/