diff mbox series

[5.13,039/380] cpufreq: schedutil: Use kobject release() method to free sugov_tunables

Message ID 20210916155805.299153663@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg KH Sept. 16, 2021, 3:56 p.m. UTC 
From: Kevin Hao <haokexin@gmail.com>

commit e5c6b312ce3cc97e90ea159446e6bfa06645364d upstream.

The struct sugov_tunables is protected by the kobject, so we can't free
it directly. Otherwise we would get a call trace like this:
  ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x30
  WARNING: CPU: 3 PID: 720 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
  Modules linked in:
  CPU: 3 PID: 720 Comm: a.sh Tainted: G        W         5.14.0-rc1-next-20210715-yocto-standard+ #507
  Hardware name: Marvell OcteonTX CN96XX board (DT)
  pstate: 40400009 (nZcv daif +PAN -UAO -TCO BTYPE=--)
  pc : debug_print_object+0xb8/0x100
  lr : debug_print_object+0xb8/0x100
  sp : ffff80001ecaf910
  x29: ffff80001ecaf910 x28: ffff00011b10b8d0 x27: ffff800011043d80
  x26: ffff00011a8f0000 x25: ffff800013cb3ff0 x24: 0000000000000000
  x23: ffff80001142aa68 x22: ffff800011043d80 x21: ffff00010de46f20
  x20: ffff800013c0c520 x19: ffff800011d8f5b0 x18: 0000000000000010
  x17: 6e6968207473696c x16: 5f72656d6974203a x15: 6570797420746365
  x14: 6a626f2029302065 x13: 303378302f307830 x12: 2b6e665f72656d69
  x11: ffff8000124b1560 x10: ffff800012331520 x9 : ffff8000100ca6b0
  x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 0000000000000001
  x5 : ffff800011d8c000 x4 : ffff800011d8c740 x3 : 0000000000000000
  x2 : ffff0001108301c0 x1 : ab3c90eedf9c0f00 x0 : 0000000000000000
  Call trace:
   debug_print_object+0xb8/0x100
   __debug_check_no_obj_freed+0x1c0/0x230
   debug_check_no_obj_freed+0x20/0x88
   slab_free_freelist_hook+0x154/0x1c8
   kfree+0x114/0x5d0
   sugov_exit+0xbc/0xc0
   cpufreq_exit_governor+0x44/0x90
   cpufreq_set_policy+0x268/0x4a8
   store_scaling_governor+0xe0/0x128
   store+0xc0/0xf0
   sysfs_kf_write+0x54/0x80
   kernfs_fop_write_iter+0x128/0x1c0
   new_sync_write+0xf0/0x190
   vfs_write+0x2d4/0x478
   ksys_write+0x74/0x100
   __arm64_sys_write+0x24/0x30
   invoke_syscall.constprop.0+0x54/0xe0
   do_el0_svc+0x64/0x158
   el0_svc+0x2c/0xb0
   el0t_64_sync_handler+0xb0/0xb8
   el0t_64_sync+0x198/0x19c
  irq event stamp: 5518
  hardirqs last  enabled at (5517): [<ffff8000100cbd7c>] console_unlock+0x554/0x6c8
  hardirqs last disabled at (5518): [<ffff800010fc0638>] el1_dbg+0x28/0xa0
  softirqs last  enabled at (5504): [<ffff8000100106e0>] __do_softirq+0x4d0/0x6c0
  softirqs last disabled at (5483): [<ffff800010049548>] irq_exit+0x1b0/0x1b8

So split the original sugov_tunables_free() into two functions,
sugov_clear_global_tunables() is just used to clear the global_tunables
and the new sugov_tunables_free() is used as kobj_type::release to
release the sugov_tunables safely.

Fixes: 9bdcb44e391d ("cpufreq: schedutil: New governor based on scheduler utilization data")
Cc: 4.7+ <stable@vger.kernel.org> # 4.7+
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/sched/cpufreq_schedutil.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

Comments

Wysocki, Rafael J Oct. 1, 2021, 5:10 p.m. UTC | #1 
On 9/17/2021 12:14 AM, Sasha Levin wrote:
> On Thu, Sep 16, 2021 at 06:55:49PM +0200, Rafael J. Wysocki wrote:

>> On 9/16/2021 5:56 PM, Greg Kroah-Hartman wrote:

>>> From: Kevin Hao <haokexin@gmail.com>

>>>

>>> commit e5c6b312ce3cc97e90ea159446e6bfa06645364d upstream.

>>>

>>> The struct sugov_tunables is protected by the kobject, so we can't free

>>> it directly. Otherwise we would get a call trace like this:

>>>   ODEBUG: free active (active state 0) object type: timer_list hint: 

>>> delayed_work_timer_fn+0x0/0x30

>>>   WARNING: CPU: 3 PID: 720 at lib/debugobjects.c:505 

>>> debug_print_object+0xb8/0x100

>>>   Modules linked in:

>>>   CPU: 3 PID: 720 Comm: a.sh Tainted: G        W 

>>> 5.14.0-rc1-next-20210715-yocto-standard+ #507

>>>   Hardware name: Marvell OcteonTX CN96XX board (DT)

>>>   pstate: 40400009 (nZcv daif +PAN -UAO -TCO BTYPE=--)

>>>   pc : debug_print_object+0xb8/0x100

>>>   lr : debug_print_object+0xb8/0x100

>>>   sp : ffff80001ecaf910

>>>   x29: ffff80001ecaf910 x28: ffff00011b10b8d0 x27: ffff800011043d80

>>>   x26: ffff00011a8f0000 x25: ffff800013cb3ff0 x24: 0000000000000000

>>>   x23: ffff80001142aa68 x22: ffff800011043d80 x21: ffff00010de46f20

>>>   x20: ffff800013c0c520 x19: ffff800011d8f5b0 x18: 0000000000000010

>>>   x17: 6e6968207473696c x16: 5f72656d6974203a x15: 6570797420746365

>>>   x14: 6a626f2029302065 x13: 303378302f307830 x12: 2b6e665f72656d69

>>>   x11: ffff8000124b1560 x10: ffff800012331520 x9 : ffff8000100ca6b0

>>>   x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 0000000000000001

>>>   x5 : ffff800011d8c000 x4 : ffff800011d8c740 x3 : 0000000000000000

>>>   x2 : ffff0001108301c0 x1 : ab3c90eedf9c0f00 x0 : 0000000000000000

>>>   Call trace:

>>>    debug_print_object+0xb8/0x100

>>>    __debug_check_no_obj_freed+0x1c0/0x230

>>>    debug_check_no_obj_freed+0x20/0x88

>>>    slab_free_freelist_hook+0x154/0x1c8

>>>    kfree+0x114/0x5d0

>>>    sugov_exit+0xbc/0xc0

>>>    cpufreq_exit_governor+0x44/0x90

>>>    cpufreq_set_policy+0x268/0x4a8

>>>    store_scaling_governor+0xe0/0x128

>>>    store+0xc0/0xf0

>>>    sysfs_kf_write+0x54/0x80

>>>    kernfs_fop_write_iter+0x128/0x1c0

>>>    new_sync_write+0xf0/0x190

>>>    vfs_write+0x2d4/0x478

>>>    ksys_write+0x74/0x100

>>>    __arm64_sys_write+0x24/0x30

>>>    invoke_syscall.constprop.0+0x54/0xe0

>>>    do_el0_svc+0x64/0x158

>>>    el0_svc+0x2c/0xb0

>>>    el0t_64_sync_handler+0xb0/0xb8

>>>    el0t_64_sync+0x198/0x19c

>>>   irq event stamp: 5518

>>>   hardirqs last  enabled at (5517): [<ffff8000100cbd7c>] 

>>> console_unlock+0x554/0x6c8

>>>   hardirqs last disabled at (5518): [<ffff800010fc0638>] 

>>> el1_dbg+0x28/0xa0

>>>   softirqs last  enabled at (5504): [<ffff8000100106e0>] 

>>> __do_softirq+0x4d0/0x6c0

>>>   softirqs last disabled at (5483): [<ffff800010049548>] 

>>> irq_exit+0x1b0/0x1b8

>>>

>>> So split the original sugov_tunables_free() into two functions,

>>> sugov_clear_global_tunables() is just used to clear the global_tunables

>>> and the new sugov_tunables_free() is used as kobj_type::release to

>>> release the sugov_tunables safely.

>>>

>>> Fixes: 9bdcb44e391d ("cpufreq: schedutil: New governor based on 

>>> scheduler utilization data")

>>> Cc: 4.7+ <stable@vger.kernel.org> # 4.7+

>>> Signed-off-by: Kevin Hao <haokexin@gmail.com>

>>> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

>>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

>>> ---

>>>  kernel/sched/cpufreq_schedutil.c |   16 +++++++++++-----

>>>  1 file changed, 11 insertions(+), 5 deletions(-)

>>>

>>> --- a/kernel/sched/cpufreq_schedutil.c

>>> +++ b/kernel/sched/cpufreq_schedutil.c

>>> @@ -536,9 +536,17 @@ static struct attribute *sugov_attrs[] =

>>>  };

>>>  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);

>>> +

>>> +    kfree(to_sugov_tunables(attr_set));

>>> +}

>>> +

>>>  static struct kobj_type sugov_tunables_ktype = {

>>>      .default_groups = sugov_groups,

>>>      .sysfs_ops = &governor_sysfs_ops,

>>> +    .release = &sugov_tunables_free,

>>>  };

>>>  /********************** cpufreq governor interface 

>>> *********************/

>>> @@ -638,12 +646,10 @@ static struct sugov_tunables *sugov_tuna

>>>      return tunables;

>>>  }

>>> -static void sugov_tunables_free(struct sugov_tunables *tunables)

>>> +static void sugov_clear_global_tunables(void)

>>>  {

>>>      if (!have_governor_per_policy())

>>>          global_tunables = NULL;

>>> -

>>> -    kfree(tunables);

>>>  }

>>>  static int sugov_init(struct cpufreq_policy *policy)

>>> @@ -706,7 +712,7 @@ out:

>>>  fail:

>>>      kobject_put(&tunables->attr_set.kobj);

>>>      policy->governor_data = NULL;

>>> -    sugov_tunables_free(tunables);

>>> +    sugov_clear_global_tunables();

>>>  stop_kthread:

>>>      sugov_kthread_stop(sg_policy);

>>> @@ -733,7 +739,7 @@ static void sugov_exit(struct cpufreq_po

>>>      count = gov_attr_set_put(&tunables->attr_set, 

>>> &sg_policy->tunables_hook);

>>>      policy->governor_data = NULL;

>>>      if (!count)

>>> -        sugov_tunables_free(tunables);

>>> +        sugov_clear_global_tunables();

>>>      mutex_unlock(&global_tunables_lock);

>>>

>>>

>> Please defer adding this one.

>

> I'll drop, let us know when to bring it back.

>

You've just picked up the commit that this one depends on ("cpufreq: 
schedutil: Destroy mutex before kobject_put() frees the memory".
diff mbox series

Patch

--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -536,9 +536,17 @@  static struct attribute *sugov_attrs[] =
 };
 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);
+
+	kfree(to_sugov_tunables(attr_set));
+}
+
 static struct kobj_type sugov_tunables_ktype = {
 	.default_groups = sugov_groups,
 	.sysfs_ops = &governor_sysfs_ops,
+	.release = &sugov_tunables_free,
 };
 
 /********************** cpufreq governor interface *********************/
@@ -638,12 +646,10 @@  static struct sugov_tunables *sugov_tuna
 	return tunables;
 }
 
-static void sugov_tunables_free(struct sugov_tunables *tunables)
+static void sugov_clear_global_tunables(void)
 {
 	if (!have_governor_per_policy())
 		global_tunables = NULL;
-
-	kfree(tunables);
 }
 
 static int sugov_init(struct cpufreq_policy *policy)
@@ -706,7 +712,7 @@  out:
 fail:
 	kobject_put(&tunables->attr_set.kobj);
 	policy->governor_data = NULL;
-	sugov_tunables_free(tunables);
+	sugov_clear_global_tunables();
 
 stop_kthread:
 	sugov_kthread_stop(sg_policy);
@@ -733,7 +739,7 @@  static void sugov_exit(struct cpufreq_po
 	count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
 	policy->governor_data = NULL;
 	if (!count)
-		sugov_tunables_free(tunables);
+		sugov_clear_global_tunables();
 
 	mutex_unlock(&global_tunables_lock);