[PATCH 1/3] cpufreq: Move to_gov_attr_set() to cpufreq.h

[PATCH 1/3] cpufreq: Move to_gov_attr_set() to cpufreq.h

[Kevin Hao]

So it can be reused by other codes.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
---
 drivers/cpufreq/cpufreq_governor_attr_set.c | 5 -----
 include/linux/cpufreq.h                     | 5 +++++
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_governor_attr_set.c b/drivers/cpufreq/cpufreq_governor_attr_set.c
index a6f365b9cc1a..771770ea0ed0 100644
--- a/drivers/cpufreq/cpufreq_governor_attr_set.c
+++ b/drivers/cpufreq/cpufreq_governor_attr_set.c
@@ -8,11 +8,6 @@
 
 #include "cpufreq_governor.h"
 
-static inline struct gov_attr_set *to_gov_attr_set(struct kobject *kobj)
-{
-	return container_of(kobj, struct gov_attr_set, kobj);
-}
-
 static inline struct governor_attr *to_gov_attr(struct attribute *attr)
 {
 	return container_of(attr, struct governor_attr, attr);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 1ab29e61b078..f0dfc0b260ec 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -658,6 +658,11 @@ struct gov_attr_set {
 /* sysfs ops for cpufreq governors */
 extern const struct sysfs_ops governor_sysfs_ops;
 
+static inline struct gov_attr_set *to_gov_attr_set(struct kobject *kobj)
+{
+	return container_of(kobj, struct gov_attr_set, kobj);
+}
+
 void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node);
 void gov_attr_set_get(struct gov_attr_set *attr_set, struct list_head *list_node);
 unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *list_node);
-- 
2.31.1

[PATCH 2/3] cpufreq: schedutil: Use to_gov_attr_set() to get the gov_attr_set

[Kevin Hao]

The to_gov_attr_set() has been moved to the cpufreq.h, so use it to get
the gov_attr_set.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
---
 kernel/sched/cpufreq_schedutil.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 26778884d9ab..cffcd08f4ec8 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -539,7 +539,7 @@ ATTRIBUTE_GROUPS(sugov);
 
 static void sugov_tunables_free(struct kobject *kobj)
 {
-	struct gov_attr_set *attr_set = container_of(kobj, struct gov_attr_set, kobj);
+	struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
 
 	kfree(to_sugov_tunables(attr_set));
 }
-- 
2.31.1

[PATCH 3/3] cpufreq: governor: Use kobject release() method to free dbs_data

[Kevin Hao]

The struct dbs_data embeds a struct gov_attr_set and
the struct gov_attr_set embeds a kobject. Since every kobject must have
a release() method and we can't use kfree() to free it directly,
so introduce cpufreq_dbs_data_release() to release the dbs_data via
the kobject::release() method. This fixes the calltrace like below:
  ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
  WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
  Modules linked in:
  CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
  Hardware name: Marvell OcteonTX CN96XX board (DT)
  pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  pc : debug_print_object+0xb8/0x100
  lr : debug_print_object+0xb8/0x100
  sp : ffff80001dfcf9a0
  x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
  x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
  x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
  x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
  x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
  x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
  x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
  x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
  x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
  x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
  Call trace:
   debug_print_object+0xb8/0x100
   __debug_check_no_obj_freed+0x1d0/0x25c
   debug_check_no_obj_freed+0x24/0xa0
   kfree+0x11c/0x440
   cpufreq_dbs_governor_exit+0xa8/0xac
   cpufreq_exit_governor+0x44/0x90
   cpufreq_set_policy+0x29c/0x570
   store_scaling_governor+0x110/0x154
   store+0xb0/0xe0
   sysfs_kf_write+0x58/0x84
   kernfs_fop_write_iter+0x12c/0x1c0
   new_sync_write+0xf0/0x18c
   vfs_write+0x1cc/0x220
   ksys_write+0x74/0x100
   __arm64_sys_write+0x28/0x3c
   invoke_syscall.constprop.0+0x58/0xf0
   do_el0_svc+0x70/0x170
   el0_svc+0x54/0x190
   el0t_64_sync_handler+0xa4/0x130
   el0t_64_sync+0x1a0/0x1a4
  irq event stamp: 189006
  hardirqs last  enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
  hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
  softirqs last  enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
  softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4

Fixes: c4435630361d ("cpufreq: governor: New sysfs show/store callbacks for governor tunables")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
---
 drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
 drivers/cpufreq/cpufreq_governor.h |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 63f7c219062b..55c80319d268 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -388,6 +388,15 @@ static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
 	gov->free(policy_dbs);
 }
 
+static void cpufreq_dbs_data_release(struct kobject *kobj)
+{
+	struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
+	struct dbs_governor *gov = dbs_data->gov;
+
+	gov->exit(dbs_data);
+	kfree(dbs_data);
+}
+
 int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 {
 	struct dbs_governor *gov = dbs_governor_of(policy);
@@ -425,6 +434,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 		goto free_policy_dbs_info;
 	}
 
+	dbs_data->gov = gov;
 	gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
 
 	ret = gov->init(dbs_data);
@@ -447,6 +457,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 	policy->governor_data = policy_dbs;
 
 	gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
+	gov->kobj_type.release = cpufreq_dbs_data_release;
 	ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
 				   get_governor_parent_kobj(policy),
 				   "%s", gov->gov.name);
@@ -488,13 +499,8 @@ void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
 
 	policy->governor_data = NULL;
 
-	if (!count) {
-		if (!have_governor_per_policy())
-			gov->gdbs_data = NULL;
-
-		gov->exit(dbs_data);
-		kfree(dbs_data);
-	}
+	if (!count && !have_governor_per_policy())
+		gov->gdbs_data = NULL;
 
 	free_policy_dbs_info(policy_dbs, gov);
 
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index bab8e6140377..a6de26318abb 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -37,6 +37,7 @@ enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
 /* Governor demand based switching data (per-policy or global). */
 struct dbs_data {
 	struct gov_attr_set attr_set;
+	struct dbs_governor *gov;
 	void *tuners;
 	unsigned int ignore_nice_load;
 	unsigned int sampling_rate;
-- 
2.31.1

Re: [PATCH 3/3] cpufreq: governor: Use kobject release() method to free dbs_data

[Rafael J. Wysocki]

On Sun, Jan 23, 2022 at 1:49 PM Kevin Hao <haokexin@gmail.com> wrote:
>
> The struct dbs_data embeds a struct gov_attr_set and
> the struct gov_attr_set embeds a kobject. Since every kobject must have
> a release() method and we can't use kfree() to free it directly,
> so introduce cpufreq_dbs_data_release() to release the dbs_data via
> the kobject::release() method. This fixes the calltrace like below:
>   ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
>   WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
>   Modules linked in:
>   CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
>   Hardware name: Marvell OcteonTX CN96XX board (DT)
>   pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>   pc : debug_print_object+0xb8/0x100
>   lr : debug_print_object+0xb8/0x100
>   sp : ffff80001dfcf9a0
>   x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
>   x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
>   x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
>   x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
>   x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
>   x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
>   x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
>   x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
>   x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
>   x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
>   Call trace:
>    debug_print_object+0xb8/0x100
>    __debug_check_no_obj_freed+0x1d0/0x25c
>    debug_check_no_obj_freed+0x24/0xa0
>    kfree+0x11c/0x440
>    cpufreq_dbs_governor_exit+0xa8/0xac
>    cpufreq_exit_governor+0x44/0x90
>    cpufreq_set_policy+0x29c/0x570
>    store_scaling_governor+0x110/0x154
>    store+0xb0/0xe0
>    sysfs_kf_write+0x58/0x84
>    kernfs_fop_write_iter+0x12c/0x1c0
>    new_sync_write+0xf0/0x18c
>    vfs_write+0x1cc/0x220
>    ksys_write+0x74/0x100
>    __arm64_sys_write+0x28/0x3c
>    invoke_syscall.constprop.0+0x58/0xf0
>    do_el0_svc+0x70/0x170
>    el0_svc+0x54/0x190
>    el0t_64_sync_handler+0xa4/0x130
>    el0t_64_sync+0x1a0/0x1a4
>   irq event stamp: 189006
>   hardirqs last  enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
>   hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
>   softirqs last  enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
>   softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4
>
> Fixes: c4435630361d ("cpufreq: governor: New sysfs show/store callbacks for governor tunables")
> Signed-off-by: Kevin Hao <haokexin@gmail.com>
> ---
>  drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
>  drivers/cpufreq/cpufreq_governor.h |  1 +
>  2 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
> index 63f7c219062b..55c80319d268 100644
> --- a/drivers/cpufreq/cpufreq_governor.c
> +++ b/drivers/cpufreq/cpufreq_governor.c
> @@ -388,6 +388,15 @@ static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
>         gov->free(policy_dbs);
>  }
>
> +static void cpufreq_dbs_data_release(struct kobject *kobj)
> +{
> +       struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
> +       struct dbs_governor *gov = dbs_data->gov;
> +
> +       gov->exit(dbs_data);
> +       kfree(dbs_data);
> +}
> +
>  int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
>  {
>         struct dbs_governor *gov = dbs_governor_of(policy);
> @@ -425,6 +434,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
>                 goto free_policy_dbs_info;
>         }
>
> +       dbs_data->gov = gov;
>         gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
>
>         ret = gov->init(dbs_data);
> @@ -447,6 +457,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
>         policy->governor_data = policy_dbs;
>
>         gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
> +       gov->kobj_type.release = cpufreq_dbs_data_release;
>         ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
>                                    get_governor_parent_kobj(policy),
>                                    "%s", gov->gov.name);
> @@ -488,13 +499,8 @@ void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
>
>         policy->governor_data = NULL;
>
> -       if (!count) {
> -               if (!have_governor_per_policy())
> -                       gov->gdbs_data = NULL;
> -
> -               gov->exit(dbs_data);

Good catch, but it is unclear to me why gov->exit() cannot be called from here.

> -               kfree(dbs_data);
> -       }
> +       if (!count && !have_governor_per_policy())
> +               gov->gdbs_data = NULL;
>
>         free_policy_dbs_info(policy_dbs, gov);
>
> diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
> index bab8e6140377..a6de26318abb 100644
> --- a/drivers/cpufreq/cpufreq_governor.h
> +++ b/drivers/cpufreq/cpufreq_governor.h
> @@ -37,6 +37,7 @@ enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
>  /* Governor demand based switching data (per-policy or global). */
>  struct dbs_data {
>         struct gov_attr_set attr_set;
> +       struct dbs_governor *gov;
>         void *tuners;
>         unsigned int ignore_nice_load;
>         unsigned int sampling_rate;
> --
> 2.31.1
>

Re: [PATCH 3/3] cpufreq: governor: Use kobject release() method to free dbs_data

[Kevin Hao]

[-- Attachment #1: Type: text/plain, Size: 6470 bytes --]

On Fri, Feb 04, 2022 at 07:19:32PM +0100, Rafael J. Wysocki wrote:
> On Sun, Jan 23, 2022 at 1:49 PM Kevin Hao <haokexin@gmail.com> wrote:
> >
> > The struct dbs_data embeds a struct gov_attr_set and
> > the struct gov_attr_set embeds a kobject. Since every kobject must have
> > a release() method and we can't use kfree() to free it directly,
> > so introduce cpufreq_dbs_data_release() to release the dbs_data via
> > the kobject::release() method. This fixes the calltrace like below:
> >   ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
> >   WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
> >   Modules linked in:
> >   CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
> >   Hardware name: Marvell OcteonTX CN96XX board (DT)
> >   pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> >   pc : debug_print_object+0xb8/0x100
> >   lr : debug_print_object+0xb8/0x100
> >   sp : ffff80001dfcf9a0
> >   x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
> >   x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
> >   x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
> >   x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
> >   x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
> >   x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
> >   x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
> >   x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
> >   x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
> >   x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
> >   Call trace:
> >    debug_print_object+0xb8/0x100
> >    __debug_check_no_obj_freed+0x1d0/0x25c
> >    debug_check_no_obj_freed+0x24/0xa0
> >    kfree+0x11c/0x440
> >    cpufreq_dbs_governor_exit+0xa8/0xac
> >    cpufreq_exit_governor+0x44/0x90
> >    cpufreq_set_policy+0x29c/0x570
> >    store_scaling_governor+0x110/0x154
> >    store+0xb0/0xe0
> >    sysfs_kf_write+0x58/0x84
> >    kernfs_fop_write_iter+0x12c/0x1c0
> >    new_sync_write+0xf0/0x18c
> >    vfs_write+0x1cc/0x220
> >    ksys_write+0x74/0x100
> >    __arm64_sys_write+0x28/0x3c
> >    invoke_syscall.constprop.0+0x58/0xf0
> >    do_el0_svc+0x70/0x170
> >    el0_svc+0x54/0x190
> >    el0t_64_sync_handler+0xa4/0x130
> >    el0t_64_sync+0x1a0/0x1a4
> >   irq event stamp: 189006
> >   hardirqs last  enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
> >   hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
> >   softirqs last  enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
> >   softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4
> >
> > Fixes: c4435630361d ("cpufreq: governor: New sysfs show/store callbacks for governor tunables")
> > Signed-off-by: Kevin Hao <haokexin@gmail.com>
> > ---
> >  drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
> >  drivers/cpufreq/cpufreq_governor.h |  1 +
> >  2 files changed, 14 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
> > index 63f7c219062b..55c80319d268 100644
> > --- a/drivers/cpufreq/cpufreq_governor.c
> > +++ b/drivers/cpufreq/cpufreq_governor.c
> > @@ -388,6 +388,15 @@ static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
> >         gov->free(policy_dbs);
> >  }
> >
> > +static void cpufreq_dbs_data_release(struct kobject *kobj)
> > +{
> > +       struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
> > +       struct dbs_governor *gov = dbs_data->gov;
> > +
> > +       gov->exit(dbs_data);
> > +       kfree(dbs_data);
> > +}
> > +
> >  int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> >  {
> >         struct dbs_governor *gov = dbs_governor_of(policy);
> > @@ -425,6 +434,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> >                 goto free_policy_dbs_info;
> >         }
> >
> > +       dbs_data->gov = gov;
> >         gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
> >
> >         ret = gov->init(dbs_data);
> > @@ -447,6 +457,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> >         policy->governor_data = policy_dbs;
> >
> >         gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
> > +       gov->kobj_type.release = cpufreq_dbs_data_release;
> >         ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
> >                                    get_governor_parent_kobj(policy),
> >                                    "%s", gov->gov.name);
> > @@ -488,13 +499,8 @@ void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
> >
> >         policy->governor_data = NULL;
> >
> > -       if (!count) {
> > -               if (!have_governor_per_policy())
> > -                       gov->gdbs_data = NULL;
> > -
> > -               gov->exit(dbs_data);
> 
> Good catch, but it is unclear to me why gov->exit() cannot be called from here.

The kobject_put(&attr_set->kobj) is invoked before this.
  cpufreq_dbs_governor_exit()
    gov_attr_set_put()
      kobject_put(&attr_set->kobj)

When the CONFIG_DEBUG_KOBJECT_RELEASE is not enabled, the invocation of kobject_put() would
cause the dbs_data to be released immediately. So we have to move the gov->exit(dbs_data) before
the release of dbs_data.

Thanks,
Kevin

> 
> > -               kfree(dbs_data);
> > -       }
> > +       if (!count && !have_governor_per_policy())
> > +               gov->gdbs_data = NULL;
> >
> >         free_policy_dbs_info(policy_dbs, gov);
> >
> > diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
> > index bab8e6140377..a6de26318abb 100644
> > --- a/drivers/cpufreq/cpufreq_governor.h
> > +++ b/drivers/cpufreq/cpufreq_governor.h
> > @@ -37,6 +37,7 @@ enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
> >  /* Governor demand based switching data (per-policy or global). */
> >  struct dbs_data {
> >         struct gov_attr_set attr_set;
> > +       struct dbs_governor *gov;
> >         void *tuners;
> >         unsigned int ignore_nice_load;
> >         unsigned int sampling_rate;
> > --
> > 2.31.1
> >

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Re: [PATCH 3/3] cpufreq: governor: Use kobject release() method to free dbs_data

[Kevin Hao]

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On Sat, Feb 05, 2022 at 07:01:30PM +0800, Kevin Hao wrote:
> On Fri, Feb 04, 2022 at 07:19:32PM +0100, Rafael J. Wysocki wrote:
> > On Sun, Jan 23, 2022 at 1:49 PM Kevin Hao <haokexin@gmail.com> wrote:
> > >
> > > The struct dbs_data embeds a struct gov_attr_set and
> > > the struct gov_attr_set embeds a kobject. Since every kobject must have
> > > a release() method and we can't use kfree() to free it directly,
> > > so introduce cpufreq_dbs_data_release() to release the dbs_data via
> > > the kobject::release() method. This fixes the calltrace like below:
> > >   ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
> > >   WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
> > >   Modules linked in:
> > >   CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
> > >   Hardware name: Marvell OcteonTX CN96XX board (DT)
> > >   pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> > >   pc : debug_print_object+0xb8/0x100
> > >   lr : debug_print_object+0xb8/0x100
> > >   sp : ffff80001dfcf9a0
> > >   x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
> > >   x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
> > >   x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
> > >   x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
> > >   x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
> > >   x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
> > >   x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
> > >   x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
> > >   x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
> > >   x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
> > >   Call trace:
> > >    debug_print_object+0xb8/0x100
> > >    __debug_check_no_obj_freed+0x1d0/0x25c
> > >    debug_check_no_obj_freed+0x24/0xa0
> > >    kfree+0x11c/0x440
> > >    cpufreq_dbs_governor_exit+0xa8/0xac
> > >    cpufreq_exit_governor+0x44/0x90
> > >    cpufreq_set_policy+0x29c/0x570
> > >    store_scaling_governor+0x110/0x154
> > >    store+0xb0/0xe0
> > >    sysfs_kf_write+0x58/0x84
> > >    kernfs_fop_write_iter+0x12c/0x1c0
> > >    new_sync_write+0xf0/0x18c
> > >    vfs_write+0x1cc/0x220
> > >    ksys_write+0x74/0x100
> > >    __arm64_sys_write+0x28/0x3c
> > >    invoke_syscall.constprop.0+0x58/0xf0
> > >    do_el0_svc+0x70/0x170
> > >    el0_svc+0x54/0x190
> > >    el0t_64_sync_handler+0xa4/0x130
> > >    el0t_64_sync+0x1a0/0x1a4
> > >   irq event stamp: 189006
> > >   hardirqs last  enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
> > >   hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
> > >   softirqs last  enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
> > >   softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4
> > >
> > > Fixes: c4435630361d ("cpufreq: governor: New sysfs show/store callbacks for governor tunables")
> > > Signed-off-by: Kevin Hao <haokexin@gmail.com>
> > > ---
> > >  drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
> > >  drivers/cpufreq/cpufreq_governor.h |  1 +
> > >  2 files changed, 14 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
> > > index 63f7c219062b..55c80319d268 100644
> > > --- a/drivers/cpufreq/cpufreq_governor.c
> > > +++ b/drivers/cpufreq/cpufreq_governor.c
> > > @@ -388,6 +388,15 @@ static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
> > >         gov->free(policy_dbs);
> > >  }
> > >
> > > +static void cpufreq_dbs_data_release(struct kobject *kobj)
> > > +{
> > > +       struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
> > > +       struct dbs_governor *gov = dbs_data->gov;
> > > +
> > > +       gov->exit(dbs_data);
> > > +       kfree(dbs_data);
> > > +}
> > > +
> > >  int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> > >  {
> > >         struct dbs_governor *gov = dbs_governor_of(policy);
> > > @@ -425,6 +434,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> > >                 goto free_policy_dbs_info;
> > >         }
> > >
> > > +       dbs_data->gov = gov;
> > >         gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
> > >
> > >         ret = gov->init(dbs_data);
> > > @@ -447,6 +457,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> > >         policy->governor_data = policy_dbs;
> > >
> > >         gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
> > > +       gov->kobj_type.release = cpufreq_dbs_data_release;
> > >         ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
> > >                                    get_governor_parent_kobj(policy),
> > >                                    "%s", gov->gov.name);
> > > @@ -488,13 +499,8 @@ void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
> > >
> > >         policy->governor_data = NULL;
> > >
> > > -       if (!count) {
> > > -               if (!have_governor_per_policy())
> > > -                       gov->gdbs_data = NULL;
> > > -
> > > -               gov->exit(dbs_data);
> > 
> > Good catch, but it is unclear to me why gov->exit() cannot be called from here.
> 
> The kobject_put(&attr_set->kobj) is invoked before this.
>   cpufreq_dbs_governor_exit()
>     gov_attr_set_put()
>       kobject_put(&attr_set->kobj)
> 
> When the CONFIG_DEBUG_KOBJECT_RELEASE is not enabled, the invocation of kobject_put() would
> cause the dbs_data to be released immediately. So we have to move the gov->exit(dbs_data) before
> the release of dbs_data.

Ping.

Thanks,
Kevin

> 
> Thanks,
> Kevin
> 
> > 
> > > -               kfree(dbs_data);
> > > -       }
> > > +       if (!count && !have_governor_per_policy())
> > > +               gov->gdbs_data = NULL;
> > >
> > >         free_policy_dbs_info(policy_dbs, gov);
> > >
> > > diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
> > > index bab8e6140377..a6de26318abb 100644
> > > --- a/drivers/cpufreq/cpufreq_governor.h
> > > +++ b/drivers/cpufreq/cpufreq_governor.h
> > > @@ -37,6 +37,7 @@ enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};
> > >  /* Governor demand based switching data (per-policy or global). */
> > >  struct dbs_data {
> > >         struct gov_attr_set attr_set;
> > > +       struct dbs_governor *gov;
> > >         void *tuners;
> > >         unsigned int ignore_nice_load;
> > >         unsigned int sampling_rate;
> > > --
> > > 2.31.1
> > >



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Re: [PATCH 3/3] cpufreq: governor: Use kobject release() method to free dbs_data

[Rafael J. Wysocki]

On Sat, Apr 9, 2022 at 2:11 PM Kevin Hao <haokexin@gmail.com> wrote:
>
> On Sat, Feb 05, 2022 at 07:01:30PM +0800, Kevin Hao wrote:
> > On Fri, Feb 04, 2022 at 07:19:32PM +0100, Rafael J. Wysocki wrote:
> > > On Sun, Jan 23, 2022 at 1:49 PM Kevin Hao <haokexin@gmail.com> wrote:
> > > >
> > > > The struct dbs_data embeds a struct gov_attr_set and
> > > > the struct gov_attr_set embeds a kobject. Since every kobject must have
> > > > a release() method and we can't use kfree() to free it directly,
> > > > so introduce cpufreq_dbs_data_release() to release the dbs_data via
> > > > the kobject::release() method. This fixes the calltrace like below:
> > > >   ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
> > > >   WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
> > > >   Modules linked in:
> > > >   CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
> > > >   Hardware name: Marvell OcteonTX CN96XX board (DT)
> > > >   pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> > > >   pc : debug_print_object+0xb8/0x100
> > > >   lr : debug_print_object+0xb8/0x100
> > > >   sp : ffff80001dfcf9a0
> > > >   x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
> > > >   x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
> > > >   x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
> > > >   x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
> > > >   x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
> > > >   x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
> > > >   x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
> > > >   x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
> > > >   x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
> > > >   x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
> > > >   Call trace:
> > > >    debug_print_object+0xb8/0x100
> > > >    __debug_check_no_obj_freed+0x1d0/0x25c
> > > >    debug_check_no_obj_freed+0x24/0xa0
> > > >    kfree+0x11c/0x440
> > > >    cpufreq_dbs_governor_exit+0xa8/0xac
> > > >    cpufreq_exit_governor+0x44/0x90
> > > >    cpufreq_set_policy+0x29c/0x570
> > > >    store_scaling_governor+0x110/0x154
> > > >    store+0xb0/0xe0
> > > >    sysfs_kf_write+0x58/0x84
> > > >    kernfs_fop_write_iter+0x12c/0x1c0
> > > >    new_sync_write+0xf0/0x18c
> > > >    vfs_write+0x1cc/0x220
> > > >    ksys_write+0x74/0x100
> > > >    __arm64_sys_write+0x28/0x3c
> > > >    invoke_syscall.constprop.0+0x58/0xf0
> > > >    do_el0_svc+0x70/0x170
> > > >    el0_svc+0x54/0x190
> > > >    el0t_64_sync_handler+0xa4/0x130
> > > >    el0t_64_sync+0x1a0/0x1a4
> > > >   irq event stamp: 189006
> > > >   hardirqs last  enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
> > > >   hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
> > > >   softirqs last  enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
> > > >   softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4
> > > >
> > > > Fixes: c4435630361d ("cpufreq: governor: New sysfs show/store callbacks for governor tunables")
> > > > Signed-off-by: Kevin Hao <haokexin@gmail.com>
> > > > ---
> > > >  drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
> > > >  drivers/cpufreq/cpufreq_governor.h |  1 +
> > > >  2 files changed, 14 insertions(+), 7 deletions(-)
> > > >
> > > > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
> > > > index 63f7c219062b..55c80319d268 100644
> > > > --- a/drivers/cpufreq/cpufreq_governor.c
> > > > +++ b/drivers/cpufreq/cpufreq_governor.c
> > > > @@ -388,6 +388,15 @@ static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
> > > >         gov->free(policy_dbs);
> > > >  }
> > > >
> > > > +static void cpufreq_dbs_data_release(struct kobject *kobj)
> > > > +{
> > > > +       struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
> > > > +       struct dbs_governor *gov = dbs_data->gov;
> > > > +
> > > > +       gov->exit(dbs_data);
> > > > +       kfree(dbs_data);
> > > > +}
> > > > +
> > > >  int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> > > >  {
> > > >         struct dbs_governor *gov = dbs_governor_of(policy);
> > > > @@ -425,6 +434,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> > > >                 goto free_policy_dbs_info;
> > > >         }
> > > >
> > > > +       dbs_data->gov = gov;
> > > >         gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
> > > >
> > > >         ret = gov->init(dbs_data);
> > > > @@ -447,6 +457,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
> > > >         policy->governor_data = policy_dbs;
> > > >
> > > >         gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
> > > > +       gov->kobj_type.release = cpufreq_dbs_data_release;
> > > >         ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
> > > >                                    get_governor_parent_kobj(policy),
> > > >                                    "%s", gov->gov.name);
> > > > @@ -488,13 +499,8 @@ void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
> > > >
> > > >         policy->governor_data = NULL;
> > > >
> > > > -       if (!count) {
> > > > -               if (!have_governor_per_policy())
> > > > -                       gov->gdbs_data = NULL;
> > > > -
> > > > -               gov->exit(dbs_data);
> > >
> > > Good catch, but it is unclear to me why gov->exit() cannot be called from here.
> >
> > The kobject_put(&attr_set->kobj) is invoked before this.
> >   cpufreq_dbs_governor_exit()
> >     gov_attr_set_put()
> >       kobject_put(&attr_set->kobj)
> >
> > When the CONFIG_DEBUG_KOBJECT_RELEASE is not enabled, the invocation of kobject_put() would
> > cause the dbs_data to be released immediately. So we have to move the gov->exit(dbs_data) before
> > the release of dbs_data.

I see, but the changelog is missing this information, so I've added
the following paragraph to it:

  Because dbs_data can be freed by the gov_attr_set_put() call
  in cpufreq_dbs_governor_exit() now, it is also necessary to put the
  invocation of the governor ->exit() callback into the new
  cpufreq_dbs_data_release() function.

and queued it up for 5.19.

Thanks!

Re: [PATCH 1/3] cpufreq: Move to_gov_attr_set() to cpufreq.h

[Rafael J. Wysocki]

On Sun, Jan 23, 2022 at 1:49 PM Kevin Hao <haokexin@gmail.com> wrote:
>
> So it can be reused by other codes.
>
> Signed-off-by: Kevin Hao <haokexin@gmail.com>
> ---
>  drivers/cpufreq/cpufreq_governor_attr_set.c | 5 -----
>  include/linux/cpufreq.h                     | 5 +++++
>  2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq_governor_attr_set.c b/drivers/cpufreq/cpufreq_governor_attr_set.c
> index a6f365b9cc1a..771770ea0ed0 100644
> --- a/drivers/cpufreq/cpufreq_governor_attr_set.c
> +++ b/drivers/cpufreq/cpufreq_governor_attr_set.c
> @@ -8,11 +8,6 @@
>
>  #include "cpufreq_governor.h"
>
> -static inline struct gov_attr_set *to_gov_attr_set(struct kobject *kobj)
> -{
> -       return container_of(kobj, struct gov_attr_set, kobj);
> -}
> -
>  static inline struct governor_attr *to_gov_attr(struct attribute *attr)
>  {
>         return container_of(attr, struct governor_attr, attr);
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 1ab29e61b078..f0dfc0b260ec 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -658,6 +658,11 @@ struct gov_attr_set {
>  /* sysfs ops for cpufreq governors */
>  extern const struct sysfs_ops governor_sysfs_ops;
>
> +static inline struct gov_attr_set *to_gov_attr_set(struct kobject *kobj)
> +{
> +       return container_of(kobj, struct gov_attr_set, kobj);
> +}
> +
>  void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node);
>  void gov_attr_set_get(struct gov_attr_set *attr_set, struct list_head *list_node);
>  unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *list_node);
> --

This one and the [2/3] have been applied as 5.18 material.

I've replied to the [3/3] directly.

Thanks!