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Date: Wed, 15 Sep 2021 15:44:41 +0000
From: Anel Orazgaliyeva <anelkz@...zon.de>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: Aman Priyadarshi <apeureka@...zon.de>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpuidle: Fix memory leaks
> On Wed, Sep 15, 2021 at 02:14:56PM +0200, Rafael J. Wysocki wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
>
>
>
> On Mon, Sep 6, 2021 at 8:35 PM Anel Orazgaliyeva <anelkz@...zon.de> wrote:
> >
> > Commit c343bf1ba5ef ("cpuidle: Fix three reference count leaks")
> > fixes the cleanup of kobjects; however, it removes kfree() calls
> > altogether, leading to memory leaks.
>
> Wait, won't the cleanup be done by cpuidle_free_state_kobj()?
For state cleanup, cpuidle_free_state_kobj() is called on the all the previously created kobjs:
error_state:
for (i = i - 1; i >= 0; i--)
cpuidle_free_state_kobj(device, i);
so we still need to cleanup the kobj created in the current iteration.
For overall sysfs, the flow is as follows:
cpuidle_register_device
ret = cpuidle_add_sysfs(dev);
if (ret)
goto out_unregister;
out_unregister:
__cpuidle_unregister_device(dev);
goto out_unlock;
so when there is an error in cpuidle_add_sysfs() dev doesn’t get freed.
>
> > Fix those and also defer the initialization of dev->kobj_dev until
> > after the error check, so that we do not end up with a dangling
> > pointer.
> >
> > Signed-off-by: Anel Orazgaliyeva <anelkz@...zon.de>
> > Suggested-by: Aman Priyadarshi <apeureka@...zon.de>
> > ---
> > drivers/cpuidle/sysfs.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
> > index 53ec9585ccd4..469e18547d06 100644
> > --- a/drivers/cpuidle/sysfs.c
> > +++ b/drivers/cpuidle/sysfs.c
> > @@ -488,6 +488,7 @@ static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
> > &kdev->kobj, "state%d", i);
> > if (ret) {
> > kobject_put(&kobj->kobj);
> > + kfree(kobj);
> > goto error_state;
> > }
> > cpuidle_add_s2idle_attr_group(kobj);
> > @@ -619,6 +620,7 @@ static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
> > &kdev->kobj, "driver");
> > if (ret) {
> > kobject_put(&kdrv->kobj);
> > + kfree(kdrv);
> > return ret;
> > }
> >
> > @@ -705,7 +707,6 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev)
> > if (!kdev)
> > return -ENOMEM;
> > kdev->dev = dev;
> > - dev->kobj_dev = kdev;
> >
> > init_completion(&kdev->kobj_unregister);
> >
> > @@ -713,9 +714,11 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev)
> > "cpuidle");
> > if (error) {
> > kobject_put(&kdev->kobj);
> > + kfree(kdev);
> > return error;
> > }
> >
> > + dev->kobj_dev = kdev;
> > kobject_uevent(&kdev->kobj, KOBJ_ADD);
> >
> > return 0;
> > --
> > 2.32.0
> >
> >
> >
> >
> > Amazon Development Center Germany GmbH
> > Krausenstr. 38
> > 10117 Berlin
> > Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
> > Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
> > Sitz: Berlin
> > Ust-ID: DE 289 237 879
On Wed, Sep 15, 2021 at 02:14:56PM +0200, Rafael J. Wysocki wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
>
>
>
> On Mon, Sep 6, 2021 at 8:35 PM Anel Orazgaliyeva <anelkz@...zon.de> wrote:
> >
> > Commit c343bf1ba5ef ("cpuidle: Fix three reference count leaks")
> > fixes the cleanup of kobjects; however, it removes kfree() calls
> > altogether, leading to memory leaks.
>
> Wait, won't the cleanup be done by cpuidle_free_state_kobj()?
>
> > Fix those and also defer the initialization of dev->kobj_dev until
> > after the error check, so that we do not end up with a dangling
> > pointer.
> >
> > Signed-off-by: Anel Orazgaliyeva <anelkz@...zon.de>
> > Suggested-by: Aman Priyadarshi <apeureka@...zon.de>
> > ---
> > drivers/cpuidle/sysfs.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
> > index 53ec9585ccd4..469e18547d06 100644
> > --- a/drivers/cpuidle/sysfs.c
> > +++ b/drivers/cpuidle/sysfs.c
> > @@ -488,6 +488,7 @@ static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
> > &kdev->kobj, "state%d", i);
> > if (ret) {
> > kobject_put(&kobj->kobj);
> > + kfree(kobj);
> > goto error_state;
> > }
> > cpuidle_add_s2idle_attr_group(kobj);
> > @@ -619,6 +620,7 @@ static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
> > &kdev->kobj, "driver");
> > if (ret) {
> > kobject_put(&kdrv->kobj);
> > + kfree(kdrv);
> > return ret;
> > }
> >
> > @@ -705,7 +707,6 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev)
> > if (!kdev)
> > return -ENOMEM;
> > kdev->dev = dev;
> > - dev->kobj_dev = kdev;
> >
> > init_completion(&kdev->kobj_unregister);
> >
> > @@ -713,9 +714,11 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev)
> > "cpuidle");
> > if (error) {
> > kobject_put(&kdev->kobj);
> > + kfree(kdev);
> > return error;
> > }
> >
> > + dev->kobj_dev = kdev;
> > kobject_uevent(&kdev->kobj, KOBJ_ADD);
> >
> > return 0;
> > --
> > 2.32.0
> >
> >
> >
> >
> > Amazon Development Center Germany GmbH
> > Krausenstr. 38
> > 10117 Berlin
> > Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
> > Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
> > Sitz: Berlin
> > Ust-ID: DE 289 237 879
> >
> >
> >
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
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