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: [email protected]
Signed-off-by: Kevin Hao <[email protected]>
---
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)
-{
- 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);
--
2.31.1
On Thu, Jul 15, 2021 at 11:56 AM Kevin Hao <[email protected]> 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: [email protected]
> Signed-off-by: Kevin Hao <[email protected]>
> ---
> 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);
>
> --
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 <[email protected]> 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: [email protected]
> > Signed-off-by: Kevin Hao <[email protected]>
> > ---
> > 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);
> >
> > --