virtio-mmio: don't break lifecycle of vm_dev

vm_dev has a separate lifecycle because it has a 'struct device'
embedded. Thus, having a release callback for it is correct.

Allocating the vm_dev struct with devres totally breaks this protection,
though. Instead of waiting for the vm_dev release callback, the memory
is freed when the platform_device is removed. Resulting in a
use-after-free when finally the callback is to be called.

To easily see the problem, compile the kernel with
CONFIG_DEBUG_KOBJECT_RELEASE and unbind with sysfs.

The fix is easy, don't use devres in this case.

Found during my research about object lifetime problems.

Fixes: 7eb781b1bbb7 ("virtio_mmio: add cleanup for virtio_mmio_probe")
Signed-off-by: Wolfram Sang <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

0 files changed, 0 insertions, 0 deletions