linux-kernel - Re: [PATCH] vfio/mdev: Fix reference count leak in add_mdev_supported

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Message-ID: <20200529161953.449ced87@x1.home>
Date:   Fri, 29 May 2020 16:19:53 -0600
From:   Alex Williamson <alex.williamson@...hat.com>
To:     wu000273@....edu
Cc:     kjlu@....edu, Kirti Wankhede <kwankhede@...dia.com>,
        Cornelia Huck <cohuck@...hat.com>, Neo Jia <cjia@...dia.com>,
        Dong Jia Shi <bjsdjshi@...ux.vnet.ibm.com>,
        Jike Song <jike.song@...el.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vfio/mdev: Fix reference count leak in
 add_mdev_supported_type.

On Wed, 27 May 2020 21:01:09 -0500
wu000273@....edu wrote:

> From: Qiushi Wu <wu000273@....edu>
> 
> kobject_init_and_add() takes reference even when it fails.
> If this function returns an error, kobject_put() must be called to
> properly clean up the memory associated with the object. Thus,
> replace kfree() by kobject_put() to fix this issue. Previous
> commit "b8eb718348b8" fixed a similar problem.
> 
> Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
> Signed-off-by: Qiushi Wu <wu000273@....edu>
> ---

Applied to vfio next branch for v5.8 with Connie's and Kirti's reviews.
Thanks,

Alex

>  drivers/vfio/mdev/mdev_sysfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
> index 8ad14e5c02bf..917fd84c1c6f 100644
> --- a/drivers/vfio/mdev/mdev_sysfs.c
> +++ b/drivers/vfio/mdev/mdev_sysfs.c
> @@ -110,7 +110,7 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
>  				   "%s-%s", dev_driver_string(parent->dev),
>  				   group->name);
>  	if (ret) {
> -		kfree(type);
> +		kobject_put(&type->kobj);
>  		return ERR_PTR(ret);
>  	}
>