diff mbox series

cpufreq: schedutil: Use kobject release() method to free sugov_tunables

Message ID 20210715095337.19453-1-haokexin@gmail.com
State Superseded
Headers show
Series cpufreq: schedutil: Use kobject release() method to free sugov_tunables | expand

Commit Message

Kevin Hao July 15, 2021, 9:53 a.m. UTC
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 add a release() method for sugov_tunables_ktype to release the
sugov_tunables safely.

Fixes: 9bdcb44e391d ("cpufreq: schedutil: New governor based on scheduler utilization data")
Cc: stable@vger.kernel.org
Signed-off-by: Kevin Hao <haokexin@gmail.com>
---
 kernel/sched/cpufreq_schedutil.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

Comments

Rafael J. Wysocki Aug. 4, 2021, 4:54 p.m. UTC | #1
On Thu, Jul 15, 2021 at 11:56 AM Kevin Hao <haokexin@gmail.com> wrote:
>

> 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 add a release() method for sugov_tunables_ktype to release the

> sugov_tunables safely.

>

> Fixes: 9bdcb44e391d ("cpufreq: schedutil: New governor based on scheduler utilization data")

> Cc: stable@vger.kernel.org

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

> ---

>  kernel/sched/cpufreq_schedutil.c | 23 ++++++++++++-----------

>  1 file changed, 12 insertions(+), 11 deletions(-)

>

> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c

> index 57124614363d..ac171496da4b 100644

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

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

> @@ -537,9 +537,17 @@ 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 *********************/

> @@ -639,14 +647,6 @@ static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_polic

>         return tunables;

>  }

>

> -static void sugov_tunables_free(struct sugov_tunables *tunables)


Rename this to sugov_clear_global_tunables() and make it take no arguments.

> -{

> -       if (!have_governor_per_policy())

> -               global_tunables = NULL;

> -

> -       kfree(tunables);


Drop just this one line from it.

> -}

> -

>  static int sugov_init(struct cpufreq_policy *policy)

>  {

>         struct sugov_policy *sg_policy;

> @@ -707,7 +707,8 @@ static int sugov_init(struct cpufreq_policy *policy)

>  fail:

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

>         policy->governor_data = NULL;

> -       sugov_tunables_free(tunables);


And call sugov_clear_global_tunables() instead of the above from here
and analogously below.

> +       if (!have_governor_per_policy())

> +               global_tunables = NULL;

>

>  stop_kthread:

>         sugov_kthread_stop(sg_policy);

> @@ -733,8 +734,8 @@ static void sugov_exit(struct cpufreq_policy *policy)

>

>         count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);

>         policy->governor_data = NULL;

> -       if (!count)

> -               sugov_tunables_free(tunables);

> +       if (!count && !have_governor_per_policy())

> +               global_tunables = NULL;

>

>         mutex_unlock(&global_tunables_lock);

>

> --
Kevin Hao Aug. 5, 2021, 7:22 a.m. UTC | #2
On Wed, Aug 04, 2021 at 06:54:10PM +0200, Rafael J. Wysocki wrote:
> On Thu, Jul 15, 2021 at 11:56 AM Kevin Hao <haokexin@gmail.com> wrote:

> >

> > 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 add a release() method for sugov_tunables_ktype to release the

> > sugov_tunables safely.

> >

> > Fixes: 9bdcb44e391d ("cpufreq: schedutil: New governor based on scheduler utilization data")

> > Cc: stable@vger.kernel.org

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

> > ---

> >  kernel/sched/cpufreq_schedutil.c | 23 ++++++++++++-----------

> >  1 file changed, 12 insertions(+), 11 deletions(-)

> >

> > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c

> > index 57124614363d..ac171496da4b 100644

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

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

> > @@ -537,9 +537,17 @@ 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 *********************/

> > @@ -639,14 +647,6 @@ static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_polic

> >         return tunables;

> >  }

> >

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

> 

> Rename this to sugov_clear_global_tunables() and make it take no arguments.


OK.

> 

> > -{

> > -       if (!have_governor_per_policy())

> > -               global_tunables = NULL;

> > -

> > -       kfree(tunables);

> 

> Drop just this one line from it.


OK.

> 

> > -}

> > -

> >  static int sugov_init(struct cpufreq_policy *policy)

> >  {

> >         struct sugov_policy *sg_policy;

> > @@ -707,7 +707,8 @@ static int sugov_init(struct cpufreq_policy *policy)

> >  fail:

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

> >         policy->governor_data = NULL;

> > -       sugov_tunables_free(tunables);

> 

> And call sugov_clear_global_tunables() instead of the above from here

> and analogously below.


Will do.

Thanks,
Kevin

> 

> > +       if (!have_governor_per_policy())

> > +               global_tunables = NULL;

> >

> >  stop_kthread:

> >         sugov_kthread_stop(sg_policy);

> > @@ -733,8 +734,8 @@ static void sugov_exit(struct cpufreq_policy *policy)

> >

> >         count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);

> >         policy->governor_data = NULL;

> > -       if (!count)

> > -               sugov_tunables_free(tunables);

> > +       if (!count && !have_governor_per_policy())

> > +               global_tunables = NULL;

> >

> >         mutex_unlock(&global_tunables_lock);

> >

> > --
diff mbox series

Patch

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 57124614363d..ac171496da4b 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -537,9 +537,17 @@  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 *********************/
@@ -639,14 +647,6 @@  static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_polic
 	return tunables;
 }
 
-static void sugov_tunables_free(struct sugov_tunables *tunables)
-{
-	if (!have_governor_per_policy())
-		global_tunables = NULL;
-
-	kfree(tunables);
-}
-
 static int sugov_init(struct cpufreq_policy *policy)
 {
 	struct sugov_policy *sg_policy;
@@ -707,7 +707,8 @@  static int sugov_init(struct cpufreq_policy *policy)
 fail:
 	kobject_put(&tunables->attr_set.kobj);
 	policy->governor_data = NULL;
-	sugov_tunables_free(tunables);
+	if (!have_governor_per_policy())
+		global_tunables = NULL;
 
 stop_kthread:
 	sugov_kthread_stop(sg_policy);
@@ -733,8 +734,8 @@  static void sugov_exit(struct cpufreq_policy *policy)
 
 	count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
 	policy->governor_data = NULL;
-	if (!count)
-		sugov_tunables_free(tunables);
+	if (!count && !have_governor_per_policy())
+		global_tunables = NULL;
 
 	mutex_unlock(&global_tunables_lock);