From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Brandewie Subject: Re: linux-next: Tree for Apr 9 [cpufreq: NULL pointer deref] Date: Mon, 15 Apr 2013 11:01:26 -0700 Message-ID: <516C4076.7070605@gmail.com> References: <1923819.6Nb81T2TR8@vostro.rjw.lan> <516C25AE.4050503@intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:message-id:date:from:user-agent:mime-version:to:cc :subject:references:in-reply-to:content-type :content-transfer-encoding; bh=OrZ1XzeF/lod0Rma+cJ0VZaqjWQoNdrBiPYNnOX+3nE=; b=iM73cgH1L30zX/hCXxK+cub33Ulp2rav4rdFK2RZvNTkDCcD7KhlOMSwf+aFb3bHzH 61eO5Zxw/pVY5ei4RA1ty+EpAXUGiuXWL2cW/XqZ7Y5ONzDBdDo9TzCfurk72HILidq2 yFkFk2lGUhN8KMmzUdjLEk1xeI7cf8OZd8StOz1wZW0DK9XQXbzvqkgMyUP2/qnReBce jNkXs9Eyp69JO1jUfC5Sgnf/v7tSCVvKFrmKUKyUKAwb+Y5vp7VeIdE55LIxDHSNPGG0 7kGeLsLvVYSEX2ntagNx6VLaApzBaXKBHbnLngQYAlSx87aldywsF2Goi0J/ZHs47bEQ hoIQ== In-Reply-To: Sender: linux-next-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: sedat.dilek@gmail.com Cc: Viresh Kumar , 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 On 04/15/2013 10:51 AM, 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... ) > Tested with: while true do echo 0 > online echo 1 > online done For several minutes and rebooting several times seems to have fixed the issue. Nathan, Sorry for calling out your patch erroneously I should have paid closer attention. Viresh you can add my Tested-by: Thanks --Dirk > - 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;