From: Viresh Kumar <viresh.kumar@linaro.org>
To: Dirk Brandewie <dirk.brandewie@gmail.com>
Cc: sedat.dilek@gmail.com, "Rafael J. Wysocki" <rjw@sisk.pl>,
Dirk Brandewie <dirk.j.brandewie@intel.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
cpufreq@vger.kernel.org, Linux PM list <linux-pm@vger.kernel.org>,
Lists linaro-kernel <linaro-kernel@lists.linaro.org>,
Nathan Zimmer <nzimmer@sgi.com>
Subject: Re: linux-next: Tree for Apr 9 [cpufreq: NULL pointer deref]
Date: Mon, 15 Apr 2013 22:52:28 +0530 [thread overview]
Message-ID: <CAKohpo=OOPBYCD_K6RLw2YrJxhMokwrOww4QM2t2T4SnGObyQQ@mail.gmail.com> (raw)
In-Reply-To: <516C25AE.4050503@intel.com>
[-- Attachment #1: Type: text/plain, Size: 3173 bytes --]
On 15 April 2013 21:37, Dirk Brandewie <dirk.brandewie@gmail.com> 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 :)
@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 <viresh.kumar@linaro.org>
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 <viresh.kumar@linaro.org>
---
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;
[-- Attachment #2: 0001-cpufreq-Don-t-call-__cpufreq_governor-for-drivers-wi.patch --]
[-- Type: application/octet-stream, Size: 2279 bytes --]
From 7352a3dd60acd389cefc40fac12837d32c8a6f26 Mon Sep 17 00:00:00 2001
Message-Id: <7352a3dd60acd389cefc40fac12837d32c8a6f26.1366046202.git.viresh.kumar@linaro.org>
From: Viresh Kumar <viresh.kumar@linaro.org>
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 <viresh.kumar@linaro.org>
---
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;
--
1.7.12.rc2.18.g61b472e
next prev parent reply other threads:[~2013-04-15 17:22 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CA+icZUU_K9PiFMqMsOEk1+c2DX8LrUojZptPiRVarv4dcB2qFA@mail.gmail.com>
2013-04-09 14:03 ` linux-next: Tree for Apr 9 [cpufreq: NULL pointer deref] Rafael J. Wysocki
2013-04-09 14:04 ` Sedat Dilek
2013-04-09 14:56 ` Viresh Kumar
2013-04-09 14:59 ` Sedat Dilek
2013-04-09 16:08 ` Sedat Dilek
2013-04-09 16:51 ` Viresh Kumar
2013-04-09 16:57 ` Sedat Dilek
2013-04-09 18:26 ` Sedat Dilek
2013-04-09 18:29 ` Sedat Dilek
2013-04-09 18:39 ` Sedat Dilek
2013-04-09 20:26 ` Sedat Dilek
2013-04-10 5:41 ` Sedat Dilek
2013-04-10 5:53 ` Sedat Dilek
2013-04-10 6:14 ` Sedat Dilek
2013-04-12 8:23 ` Viresh Kumar
2013-04-12 14:24 ` Sedat Dilek
2013-04-12 15:45 ` Sedat Dilek
2013-04-12 16:27 ` Sedat Dilek
2013-04-12 21:08 ` Sedat Dilek
2013-04-12 22:51 ` Rafael J. Wysocki
2013-04-13 9:55 ` Sedat Dilek
2013-04-15 16:07 ` Dirk Brandewie
2013-04-15 16:13 ` Sedat Dilek
2013-04-15 17:22 ` Viresh Kumar [this message]
2013-04-15 17:51 ` Sedat Dilek
2013-04-15 17:57 ` Sedat Dilek
2013-04-15 18:07 ` Sedat Dilek
2013-04-15 18:01 ` Dirk Brandewie
2013-04-17 14:04 ` Sedat Dilek
2013-04-17 16:14 ` Rafael J. Wysocki
2013-04-21 23:30 ` Rafael J. Wysocki
2013-04-22 3:14 ` Viresh Kumar
2013-04-22 12:00 ` Rafael J. Wysocki
2013-04-15 17:27 ` Nathan Zimmer
2013-04-15 17:42 ` Dirk Brandewie
2013-04-15 18:05 ` Nathan Zimmer
2013-04-09 14:59 ` Viresh Kumar
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