Re: [PATCH 1/5] PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

Re: [PATCH 1/5] PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4458 bytes --]

:::::: 
:::::: Manual check reason: "low confidence static check warning: drivers/devfreq/governor_passive.c:238:24: warning: Uninitialized variable: parent_cpu_data->opp_table [uninitvar]"
:::::: 

CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
In-Reply-To: <20220606111104.14534-2-ansuelsmth@gmail.com>
References: <20220606111104.14534-2-ansuelsmth@gmail.com>
TO: "Christian 'Ansuel' Marangi" <ansuelsmth@gmail.com>
TO: MyungJoo Ham <myungjoo.ham@samsung.com>
TO: Kyungmin Park <kyungmin.park@samsung.com>
TO: Chanwoo Choi <cw00.choi@samsung.com>
TO: Saravana Kannan <skannan@codeaurora.org>
TO: Sibi Sankar <sibis@codeaurora.org>
TO: linux-pm(a)vger.kernel.org
TO: linux-kernel(a)vger.kernel.org
CC: "Christian 'Ansuel' Marangi" <ansuelsmth@gmail.com>

Hi Christian,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on chanwoo/devfreq-testing]
[also build test WARNING on linus/master v5.19-rc1 next-20220606]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Ansuel-Marangi/PM-devfreq-Various-Fixes-to-cpufreq-based-passive-governor/20220606-191335
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git devfreq-testing
:::::: branch date: 16 hours ago
:::::: commit date: 16 hours ago
compiler: riscv64-linux-gcc (GCC) 11.3.0
reproduce (cppcheck warning):
        # apt-get install cppcheck
        git checkout 2d59e1f0c418bf7a6fb2396c60a643994b4c4aba
        cppcheck --quiet --enable=style,performance,portability --template=gcc FILE

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>


cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> drivers/devfreq/governor_passive.c:238:24: warning: Uninitialized variable: parent_cpu_data->opp_table [uninitvar]
     if (parent_cpu_data->opp_table)
                          ^

vim +238 drivers/devfreq/governor_passive.c

a03dacb0316f74 Saravana Kannan            2021-03-02  220  
a03dacb0316f74 Saravana Kannan            2021-03-02  221  static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
a03dacb0316f74 Saravana Kannan            2021-03-02  222  {
a03dacb0316f74 Saravana Kannan            2021-03-02  223  	struct devfreq_passive_data *p_data
a03dacb0316f74 Saravana Kannan            2021-03-02  224  			= (struct devfreq_passive_data *)devfreq->data;
a03dacb0316f74 Saravana Kannan            2021-03-02  225  	struct devfreq_cpu_data *parent_cpu_data;
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  226  	int ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  227  
a03dacb0316f74 Saravana Kannan            2021-03-02  228  	if (p_data->nb.notifier_call) {
a03dacb0316f74 Saravana Kannan            2021-03-02  229  		ret = cpufreq_unregister_notifier(&p_data->nb,
a03dacb0316f74 Saravana Kannan            2021-03-02  230  					CPUFREQ_TRANSITION_NOTIFIER);
a03dacb0316f74 Saravana Kannan            2021-03-02  231  		if (ret < 0)
a03dacb0316f74 Saravana Kannan            2021-03-02  232  			return ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  233  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  234  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  235  	list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node) {
26984d9d581e50 Chanwoo Choi               2022-04-27  236  		list_del(&parent_cpu_data->node);
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  237  
a03dacb0316f74 Saravana Kannan            2021-03-02 @238  		if (parent_cpu_data->opp_table)
a03dacb0316f74 Saravana Kannan            2021-03-02  239  			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  240  
a03dacb0316f74 Saravana Kannan            2021-03-02  241  		kfree(parent_cpu_data);
a03dacb0316f74 Saravana Kannan            2021-03-02  242  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  243  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  244  	return 0;
a03dacb0316f74 Saravana Kannan            2021-03-02  245  }
a03dacb0316f74 Saravana Kannan            2021-03-02  246  

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [PATCH 1/5] PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4116 bytes --]

CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
In-Reply-To: <20220606111104.14534-2-ansuelsmth@gmail.com>
References: <20220606111104.14534-2-ansuelsmth@gmail.com>
TO: "Christian 'Ansuel' Marangi" <ansuelsmth@gmail.com>
TO: MyungJoo Ham <myungjoo.ham@samsung.com>
TO: Kyungmin Park <kyungmin.park@samsung.com>
TO: Chanwoo Choi <cw00.choi@samsung.com>
TO: Saravana Kannan <skannan@codeaurora.org>
TO: Sibi Sankar <sibis@codeaurora.org>
TO: linux-pm(a)vger.kernel.org
TO: linux-kernel(a)vger.kernel.org
CC: "Christian 'Ansuel' Marangi" <ansuelsmth@gmail.com>

Hi Christian,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on chanwoo/devfreq-testing]
[also build test WARNING on linus/master v5.19-rc1 next-20220609]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Ansuel-Marangi/PM-devfreq-Various-Fixes-to-cpufreq-based-passive-governor/20220606-191335
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git devfreq-testing
:::::: branch date: 4 days ago
:::::: commit date: 4 days ago
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220610/202206101102.4JCYtCjM-lkp(a)intel.com/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/devfreq/governor_passive.c:235 cpufreq_passive_unregister_notifier() error: dereferencing freed memory 'parent_cpu_data'

vim +/parent_cpu_data +235 drivers/devfreq/governor_passive.c

a03dacb0316f74 Saravana Kannan            2021-03-02  220  
a03dacb0316f74 Saravana Kannan            2021-03-02  221  static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
a03dacb0316f74 Saravana Kannan            2021-03-02  222  {
a03dacb0316f74 Saravana Kannan            2021-03-02  223  	struct devfreq_passive_data *p_data
a03dacb0316f74 Saravana Kannan            2021-03-02  224  			= (struct devfreq_passive_data *)devfreq->data;
a03dacb0316f74 Saravana Kannan            2021-03-02  225  	struct devfreq_cpu_data *parent_cpu_data;
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  226  	int ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  227  
a03dacb0316f74 Saravana Kannan            2021-03-02  228  	if (p_data->nb.notifier_call) {
a03dacb0316f74 Saravana Kannan            2021-03-02  229  		ret = cpufreq_unregister_notifier(&p_data->nb,
a03dacb0316f74 Saravana Kannan            2021-03-02  230  					CPUFREQ_TRANSITION_NOTIFIER);
a03dacb0316f74 Saravana Kannan            2021-03-02  231  		if (ret < 0)
a03dacb0316f74 Saravana Kannan            2021-03-02  232  			return ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  233  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  234  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06 @235  	list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node) {
26984d9d581e50 Chanwoo Choi               2022-04-27  236  		list_del(&parent_cpu_data->node);
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  237  
a03dacb0316f74 Saravana Kannan            2021-03-02  238  		if (parent_cpu_data->opp_table)
a03dacb0316f74 Saravana Kannan            2021-03-02  239  			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  240  
a03dacb0316f74 Saravana Kannan            2021-03-02  241  		kfree(parent_cpu_data);
a03dacb0316f74 Saravana Kannan            2021-03-02  242  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  243  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  244  	return 0;
a03dacb0316f74 Saravana Kannan            2021-03-02  245  }
a03dacb0316f74 Saravana Kannan            2021-03-02  246  

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [PATCH 1/5] PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

[Dan Carpenter]

[-- Attachment #1: Type: text/plain, Size: 3125 bytes --]

Hi Christian,

url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Ansuel-Marangi/PM-devfreq-Various-Fixes-to-cpufreq-based-passive-governor/20220606-191335
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git devfreq-testing
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220610/202206101102.4JCYtCjM-lkp(a)intel.com/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/devfreq/governor_passive.c:235 cpufreq_passive_unregister_notifier() error: dereferencing freed memory 'parent_cpu_data'

vim +/parent_cpu_data +235 drivers/devfreq/governor_passive.c

a03dacb0316f74 Saravana Kannan            2021-03-02  221  static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
a03dacb0316f74 Saravana Kannan            2021-03-02  222  {
a03dacb0316f74 Saravana Kannan            2021-03-02  223  	struct devfreq_passive_data *p_data
a03dacb0316f74 Saravana Kannan            2021-03-02  224  			= (struct devfreq_passive_data *)devfreq->data;
a03dacb0316f74 Saravana Kannan            2021-03-02  225  	struct devfreq_cpu_data *parent_cpu_data;
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  226  	int ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  227  
a03dacb0316f74 Saravana Kannan            2021-03-02  228  	if (p_data->nb.notifier_call) {
a03dacb0316f74 Saravana Kannan            2021-03-02  229  		ret = cpufreq_unregister_notifier(&p_data->nb,
a03dacb0316f74 Saravana Kannan            2021-03-02  230  					CPUFREQ_TRANSITION_NOTIFIER);
a03dacb0316f74 Saravana Kannan            2021-03-02  231  		if (ret < 0)
a03dacb0316f74 Saravana Kannan            2021-03-02  232  			return ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  233  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  234  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06 @235  	list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node) {

This needs to be list_for_each_entry_safe()

26984d9d581e50 Chanwoo Choi               2022-04-27  236  		list_del(&parent_cpu_data->node);

Otherwise it will only iterate one time

2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  237  
a03dacb0316f74 Saravana Kannan            2021-03-02  238  		if (parent_cpu_data->opp_table)
a03dacb0316f74 Saravana Kannan            2021-03-02  239  			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  240  
a03dacb0316f74 Saravana Kannan            2021-03-02  241  		kfree(parent_cpu_data);

And it will dereference a freed pointer

a03dacb0316f74 Saravana Kannan            2021-03-02  242  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  243  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  244  	return 0;
a03dacb0316f74 Saravana Kannan            2021-03-02  245  }

-- 
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https://01.org/lkp

Re: [PATCH 1/5] PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

[Dan Carpenter]

Hi Christian,

url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Ansuel-Marangi/PM-devfreq-Various-Fixes-to-cpufreq-based-passive-governor/20220606-191335
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git devfreq-testing
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220610/202206101102.4JCYtCjM-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/devfreq/governor_passive.c:235 cpufreq_passive_unregister_notifier() error: dereferencing freed memory 'parent_cpu_data'

vim +/parent_cpu_data +235 drivers/devfreq/governor_passive.c

a03dacb0316f74 Saravana Kannan            2021-03-02  221  static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
a03dacb0316f74 Saravana Kannan            2021-03-02  222  {
a03dacb0316f74 Saravana Kannan            2021-03-02  223  	struct devfreq_passive_data *p_data
a03dacb0316f74 Saravana Kannan            2021-03-02  224  			= (struct devfreq_passive_data *)devfreq->data;
a03dacb0316f74 Saravana Kannan            2021-03-02  225  	struct devfreq_cpu_data *parent_cpu_data;
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  226  	int ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  227  
a03dacb0316f74 Saravana Kannan            2021-03-02  228  	if (p_data->nb.notifier_call) {
a03dacb0316f74 Saravana Kannan            2021-03-02  229  		ret = cpufreq_unregister_notifier(&p_data->nb,
a03dacb0316f74 Saravana Kannan            2021-03-02  230  					CPUFREQ_TRANSITION_NOTIFIER);
a03dacb0316f74 Saravana Kannan            2021-03-02  231  		if (ret < 0)
a03dacb0316f74 Saravana Kannan            2021-03-02  232  			return ret;
a03dacb0316f74 Saravana Kannan            2021-03-02  233  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  234  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06 @235  	list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node) {

This needs to be list_for_each_entry_safe()

26984d9d581e50 Chanwoo Choi               2022-04-27  236  		list_del(&parent_cpu_data->node);

Otherwise it will only iterate one time

2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  237  
a03dacb0316f74 Saravana Kannan            2021-03-02  238  		if (parent_cpu_data->opp_table)
a03dacb0316f74 Saravana Kannan            2021-03-02  239  			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  240  
a03dacb0316f74 Saravana Kannan            2021-03-02  241  		kfree(parent_cpu_data);

And it will dereference a freed pointer

a03dacb0316f74 Saravana Kannan            2021-03-02  242  	}
a03dacb0316f74 Saravana Kannan            2021-03-02  243  
2d59e1f0c418bf Christian 'Ansuel' Marangi 2022-06-06  244  	return 0;
a03dacb0316f74 Saravana Kannan            2021-03-02  245  }

-- 
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[PATCH 0/5] PM / devfreq: Various Fixes to cpufreq based passive governor

[Christian 'Ansuel' Marangi]

While developing a krait cache scaling devfreq driver I encounter tons
of panics and errors with using the new cpufreq passive governor
functions. While the krait cache scaling is still WIP and required some
testing I would like to push all the fixes to make the new
implementation wroking since currently with a the governor
PROBE_DEFERRing all sort of things happen from kernel panic from invalid
address access to freq_table getting corrupted.

With the following fixes my WIP driver works correctly without any
warning/problems. 

Christian 'Ansuel' Marangi (5):
  PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER
  PM / devfreq: Fix kernel warning with cpufreq passive register fail
  PM / devfreq: Fix kernel panic with cpu based scaling to passive gov
  PM / devfreq: Rework freq_table to be local to devfreq struct
  PM / devfreq: Mute warning on governor PROBE_DEFER

 drivers/devfreq/devfreq.c          | 75 ++++++++++++++----------------
 drivers/devfreq/governor_passive.c | 39 ++++++----------
 include/linux/devfreq.h            |  4 ++
 3 files changed, 53 insertions(+), 65 deletions(-)

-- 
2.36.1

[PATCH 1/5] PM / devfreq: Fix cpufreq passive unregister erroring on PROBE_DEFER

[Christian 'Ansuel' Marangi]

With the passive governor, the cpu based scaling can PROBE_DEFER due to
the fact that CPU policy are not ready.
The cpufreq passive unregister notifier is called both from the
GOV_START errors and for the GOV_STOP and assume the notifier is
successfully registred every time. With GOV_START failing it's wrong to
loop over each possible CPU since the register path has failed for
some CPU policy not ready. Change the logic and unregister the notifer
based on the current allocated parent_cpu_data list to correctly handle
errors and the governor unregister path.

Fixes: a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor")
Signed-off-by: Christian 'Ansuel' Marangi <ansuelsmth@gmail.com>
---
 drivers/devfreq/governor_passive.c | 21 +++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index 72c67979ebe1..09b6c852fccc 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -223,7 +223,7 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 	struct devfreq_passive_data *p_data
 			= (struct devfreq_passive_data *)devfreq->data;
 	struct devfreq_cpu_data *parent_cpu_data;
-	int cpu, ret = 0;
+	int ret;
 
 	if (p_data->nb.notifier_call) {
 		ret = cpufreq_unregister_notifier(&p_data->nb,
@@ -232,27 +232,16 @@ static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
 			return ret;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-		if (!policy) {
-			ret = -EINVAL;
-			continue;
-		}
-
-		parent_cpu_data = get_parent_cpu_data(p_data, policy);
-		if (!parent_cpu_data) {
-			cpufreq_cpu_put(policy);
-			continue;
-		}
-
+	list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node) {
 		list_del(&parent_cpu_data->node);
+
 		if (parent_cpu_data->opp_table)
 			dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
 		kfree(parent_cpu_data);
-		cpufreq_cpu_put(policy);
 	}
 
-	return ret;
+	return 0;
 }
 
 static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
-- 
2.36.1