Re: [PATCH v2] s390/vfio-ap: Fix module unload memory leak of matrix_dev

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 6/18/21 2:23 PM, Jason Gunthorpe wrote:
On Fri, Jun 18, 2021 at 02:11:23PM -0400, Tony Krowiak wrote:

On 6/18/21 1:12 PM, Jason J. Herne wrote:
vfio_ap_matrix_dev_release is shadowing the global matrix_dev with a NULL
pointer. Driver data for the matrix device is never set and so
dev_get_drvdata() always returns NULL. When release is called we end up
not freeing matrix_dev. The fix is to remove the shadow variable and get
the correct pointer from the device using container_of. We'll also NULL
the global to prevent any future use.

Signed-off-by: Jason J. Herne <jjherne@xxxxxxxxxxxxx>
   drivers/s390/crypto/vfio_ap_drv.c | 5 ++---
   1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index 7dc72cb718b0..40e66cb363d1 100644
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -82,9 +82,8 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
   static void vfio_ap_matrix_dev_release(struct device *dev)
   {
-	struct ap_matrix_dev *matrix_dev = dev_get_drvdata(dev);
-
-	kfree(matrix_dev);
+	kfree(container_of(dev, struct ap_matrix_dev, device));
I suppose if we're not going to assume that the release is being
called to free the global matrix_dev, then if you are going to
retrieve it using container_of(), then maybe we should verify
the retrieved pointer is the same as the global matrix_dev?
That seems like overkill to me

After thinking about it, it's probably more than overkill as I
assume the container_of() function would fail if dev was
not contained in matrix_mdev:

Reviewed-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>


Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Jason




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux