linux-kernel - Re: [PATCH] cpuidle: Fix memory leaks

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Date:   Wed, 15 Sep 2021 14:14:56 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Anel Orazgaliyeva <anelkz@...zon.de>
Cc:     Aman Priyadarshi <apeureka@...zon.de>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpuidle: Fix memory leaks

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
>
>
>
>
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