cpufreq: Move to_gov_attr_set() to cpufreq.h

PATCH Superseded Kevin Hao 2 participants 8 messages Jan 23, 2022 – Apr 13, 2022

Subsystems (2)

Scheduler CPU frequency scaling framework

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Kevin Hao

author

2022-01-23 12:49 UTC #0 lore raw

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

So it can be reused by other codes.

Signed-off-by Kevin Hao <[email protected]>

---
 drivers/cpufreq/cpufreq_governor_attr_set.c | 5 -----
 include/linux/cpufreq.h                     | 5 +++++
 2 files changed, 5 insertions(+), 5 deletions(-)

drivers/cpufreq/cpufreq_governor_attr_set.c +0 -5

index a6f365b9cc1a..771770ea0ed0 100644
@@ -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);

include/linux/cpufreq.h +5 -0

index 1ab29e61b078..f0dfc0b260ec 100644
@@ -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);

Signature · 1 line

2.31.1

Kevin Hao

author

2022-01-23 12:49 UTC #1 lore raw

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

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 <[email protected]>

---
 kernel/sched/cpufreq_schedutil.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/sched/cpufreq_schedutil.c +1 -1

index 26778884d9ab..cffcd08f4ec8 100644
@@ -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));
 }

Signature · 1 line

2.31.1

Kevin Hao

author

2022-01-23 12:49 UTC #2 lore raw

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

In reply to 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 <[email protected]>

---
 drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
 drivers/cpufreq/cpufreq_governor.h |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

drivers/cpufreq/cpufreq_governor.c +13 -7

index 63f7c219062b..55c80319d268 100644
@@ -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);

drivers/cpufreq/cpufreq_governor.h +1 -0

index bab8e6140377..a6de26318abb 100644
@@ -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;

Signature · 1 line

2.31.1

Rafael J. Wysocki

maintainer

2022-02-04 18:19 UTC #3 lore raw

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

Quoted 96 lines · Kevin Hao

  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 <[email protected]>

---
 drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
 drivers/cpufreq/cpufreq_governor.h |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

drivers/cpufreq/cpufreq_governor.c +11 -0

index 63f7c219062b..55c80319d268 100644
@@ -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);

drivers/cpufreq/cpufreq_governor.c void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy) · line 495

Quoted 8 lines

drivers/cpufreq/cpufreq_governor.c +0 -5

@@ -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.

Quoted 22 lines

drivers/cpufreq/cpufreq_governor.c +2 -2

-               kfree(dbs_data);
-       }
+       if (!count && !have_governor_per_policy())
+               gov->gdbs_data = NULL;
 
        free_policy_dbs_info(policy_dbs, gov);

drivers/cpufreq/cpufreq_governor.h +1 -1

index bab8e6140377..a6de26318abb 100644
@@ -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

Kevin Hao

author

2022-02-05 11:01 UTC #4 lore raw

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

Quoted 100 lines · Rafael J. Wysocki

Quoted 99 lines · Kevin Hao

  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 <[email protected]>

---
 drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
 drivers/cpufreq/cpufreq_governor.h |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

drivers/cpufreq/cpufreq_governor.c +11 -0

index 63f7c219062b..55c80319d268 100644
@@ -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;

Quoted 7 lines

drivers/cpufreq/cpufreq_governor.c void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy) · line 495
Quoted 5 lines
drivers/cpufreq/cpufreq_governor.c +0 -5
-       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

Quoted 23 lines

drivers/cpufreq/cpufreq_governor.c +2 -2

-               kfree(dbs_data);
-       }
+       if (!count && !have_governor_per_policy())
+               gov->gdbs_data = NULL;
 
        free_policy_dbs_info(policy_dbs, gov);

drivers/cpufreq/cpufreq_governor.h +1 -1

index bab8e6140377..a6de26318abb 100644
@@ -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

Kevin Hao

author

2022-04-09 12:11 UTC #5 lore raw

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

Quoted 109 lines · Kevin Hao

Quoted 100 lines · Rafael J. Wysocki

Quoted 99 lines · Kevin Hao

  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 <[email protected]>

---
 drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
 drivers/cpufreq/cpufreq_governor.h |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

drivers/cpufreq/cpufreq_governor.c +11 -0

index 63f7c219062b..55c80319d268 100644
@@ -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;

Quoted 7 lines

drivers/cpufreq/cpufreq_governor.c void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy) · line 495
Quoted 5 lines
drivers/cpufreq/cpufreq_governor.c +0 -5
-       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.

Quoted 8 lines

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

Quoted 27 lines

Thanks,
Kevin

Quoted 23 lines

drivers/cpufreq/cpufreq_governor.c +2 -2

-               kfree(dbs_data);
-       }
+       if (!count && !have_governor_per_policy())
+               gov->gdbs_data = NULL;
 
        free_policy_dbs_info(policy_dbs, gov);

drivers/cpufreq/cpufreq_governor.h +1 -1

index bab8e6140377..a6de26318abb 100644
@@ -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

Rafael J. Wysocki

maintainer

2022-04-13 13:30 UTC #6 lore raw

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

Quoted 111 lines · Kevin Hao

Quoted 109 lines · Kevin Hao

Quoted 107 lines · Rafael J. Wysocki

Quoted 96 lines · Kevin Hao

  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 <[email protected]>

---
 drivers/cpufreq/cpufreq_governor.c | 20 +++++++++++++-------
 drivers/cpufreq/cpufreq_governor.h |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

drivers/cpufreq/cpufreq_governor.c +11 -0

index 63f7c219062b..55c80319d268 100644
@@ -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);

drivers/cpufreq/cpufreq_governor.c void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy) · line 495

Quoted 8 lines

drivers/cpufreq/cpufreq_governor.c +0 -5

@@ -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.

Quoted 8 lines

Quoted 8 lines
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!

Rafael J. Wysocki

maintainer

2022-02-04 18:25 UTC #7 lore raw

In reply to Kevin Hao

Quoted 32 lines · Kevin Hao

So it can be reused by other codes.

Signed-off-by Kevin Hao <[email protected]>

---
 drivers/cpufreq/cpufreq_governor_attr_set.c | 5 -----
 include/linux/cpufreq.h                     | 5 +++++
 2 files changed, 5 insertions(+), 5 deletions(-)

drivers/cpufreq/cpufreq_governor_attr_set.c +0 -5

index a6f365b9cc1a..771770ea0ed0 100644
@@ -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);

include/linux/cpufreq.h +0 -0

index 1ab29e61b078..f0dfc0b260ec 100644
@@ -658,6 +658,11 @@ struct gov_attr_set {
 /* sysfs ops for cpufreq governors */
 extern const struct sysfs_ops governor_sysfs_ops;

include/linux/cpufreq.h struct gov_attr_set {

Quoted 10 lines

include/linux/cpufreq.h +5 -1

 
+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!