| Message ID | 20230315153932.165031-1-akrowiak@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390/vfio_ap: fix memory leak in vfio_ap device driver | expand |
On 2023-03-15 16:39, 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 <akrowiak@linux.ibm.com> > --- > drivers/s390/crypto/vfio_ap_drv.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_drv.c > b/drivers/s390/crypto/vfio_ap_drv.c > index 997b524bdd2b..15e9de9f4574 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 = container_of(dev, > + struct ap_matrix_dev, > + device); > kfree(matrix_dev); > } I needed some indirections to follow what exactly happens here and how you fix it, but finally I got it. Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
snip ... > I needed some indirections to follow what exactly happens here and how > you > fix it, but finally I got it. > Reviewed-by: Harald Freudenberger <freude@linux.ibm.com> Sorry about the indirections. Thanks for the review.
On Wed, Mar 15, 2023 at 11:39:32AM -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 <akrowiak@linux.ibm.com> > --- > drivers/s390/crypto/vfio_ap_drv.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c > index 997b524bdd2b..15e9de9f4574 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 = container_of(dev, > + struct ap_matrix_dev, > + device); > kfree(matrix_dev); Could you keep this code more readable, including adding the missing blank line after the declaration, please? Something like: static void vfio_ap_matrix_dev_release(struct device *dev) { struct ap_matrix_dev *matrix_dev; matrix_dev = container_of(dev, struct ap_matrix_dev, device); kfree(matrix_dev); } Thanks!
On 3/16/23 4:39 AM, Heiko Carstens wrote: > On Wed, Mar 15, 2023 at 11:39:32AM -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 <akrowiak@linux.ibm.com> >> --- >> drivers/s390/crypto/vfio_ap_drv.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c >> index 997b524bdd2b..15e9de9f4574 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 = container_of(dev, >> + struct ap_matrix_dev, >> + device); >> kfree(matrix_dev); > Could you keep this code more readable, including adding the missing > blank line after the declaration, please? Something like: > > static void vfio_ap_matrix_dev_release(struct device *dev) > { > struct ap_matrix_dev *matrix_dev; > > matrix_dev = container_of(dev, struct ap_matrix_dev, device); > kfree(matrix_dev); > } > > Thanks! Will do.
diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c index 997b524bdd2b..15e9de9f4574 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 = container_of(dev, + struct ap_matrix_dev, + device); kfree(matrix_dev); }
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 <akrowiak@linux.ibm.com> --- drivers/s390/crypto/vfio_ap_drv.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)