In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: fix memory leak in vfioap device driver The device release callback function invoked to release the matrix device uses the devgetdrvdata(device *dev) function to retrieve the pointer to the vfiomatrixdev 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 vfiomatrixdev object is never freed. Since the device being released is contained within the vfiomatrixdev object, the containerof macro will be used to retrieve its pointer.