Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934684Ab3DOR5W (ORCPT ); Mon, 15 Apr 2013 13:57:22 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:40421 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934052Ab3DOR5U (ORCPT ); Mon, 15 Apr 2013 13:57:20 -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 19:57:17 +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: 4857 Lines: 139 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. > > ( Dirk promised to test as well... ) > 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/