2023-03-20 15:10:41

by Anthony Krowiak

Subject: [PATCH v2] s390/vfio_ap: fix memory leak in vfio_ap device driver

The device release callback function invoked to release the matrix device
uses the dev_get_drvdata(device *dev) function to retrieve the
pointer to the vfio_matrix_dev object in order to free its storage. The
problem is, this object is not stored as drvdata with the device; since the
kfree function will accept a NULL pointer, the memory for the
vfio_matrix_dev object is never freed.

Since the device being released is contained within the vfio_matrix_dev
object, the container_of macro will be used to retrieve its pointer.

Fixes: 1fde573413b5 ("s390: vfio-ap: base implementation of VFIO AP device driver")
Signed-off-by: Tony Krowiak <[email protected]>
Reviewed-by: Harald Freudenberger <[email protected]>
---
drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index 997b524bdd2b..a48c6938ae68 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -54,8 +54,9 @@ static struct ap_driver vfio_ap_drv = {

static void vfio_ap_matrix_dev_release(struct device *dev)
{
- struct ap_matrix_dev *matrix_dev = dev_get_drvdata(dev);
+ struct ap_matrix_dev *matrix_dev;

+ matrix_dev = container_of(dev, struct ap_matrix_dev, device);
kfree(matrix_dev);
}

--
2.31.1

2023-03-21 12:47:57

by Anthony Krowiak

Subject: Re: [PATCH v2] s390/vfio_ap: fix memory leak in vfio_ap device driver

PING!

On 3/20/23 11:04 AM, Tony Krowiak wrote:
> The device release callback function invoked to release the matrix device
> uses the dev_get_drvdata(device *dev) function to retrieve the
> pointer to the vfio_matrix_dev object in order to free its storage. The
> problem is, this object is not stored as drvdata with the device; since the
> kfree function will accept a NULL pointer, the memory for the
> vfio_matrix_dev object is never freed.
>
> Since the device being released is contained within the vfio_matrix_dev
> object, the container_of macro will be used to retrieve its pointer.
>
> Fixes: 1fde573413b5 ("s390: vfio-ap: base implementation of VFIO AP device driver")
> Signed-off-by: Tony Krowiak <[email protected]>
> Reviewed-by: Harald Freudenberger <[email protected]>
> ---
> drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 997b524bdd2b..a48c6938ae68 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -54,8 +54,9 @@ static struct ap_driver vfio_ap_drv = {
>
> static void vfio_ap_matrix_dev_release(struct device *dev)
> {
> - struct ap_matrix_dev *matrix_dev = dev_get_drvdata(dev);
> + struct ap_matrix_dev *matrix_dev;
>
> + matrix_dev = container_of(dev, struct ap_matrix_dev, device);
> kfree(matrix_dev);
> }
>

2023-03-21 13:41:57

by Heiko Carstens

Subject: Re: [PATCH v2] s390/vfio_ap: fix memory leak in vfio_ap device driver

On Mon, Mar 20, 2023 at 11:04:47AM -0400, Tony Krowiak wrote:
> The device release callback function invoked to release the matrix device
> uses the dev_get_drvdata(device *dev) function to retrieve the
> pointer to the vfio_matrix_dev object in order to free its storage. The
> problem is, this object is not stored as drvdata with the device; since the
> kfree function will accept a NULL pointer, the memory for the
> vfio_matrix_dev object is never freed.
>
> Since the device being released is contained within the vfio_matrix_dev
> object, the container_of macro will be used to retrieve its pointer.
>
> Fixes: 1fde573413b5 ("s390: vfio-ap: base implementation of VFIO AP device driver")
> Signed-off-by: Tony Krowiak <[email protected]>
> Reviewed-by: Harald Freudenberger <[email protected]>
> ---
> drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

Applied.