CVE-2026-31399

In the Linux kernel, the following vulnerability has been resolved:

nvdimm/bus: Fix potential use after free in asynchronous initialization

Dingisoul with KASAN reports a use after free if device_add() fails in
nd_async_device_register().

Commit b6eae0f61db2 ("libnvdimm: Hold reference on parent while
scheduling async init") correctly added a reference on the parent device
to be held until asynchronous initialization was complete.  However, if
device_add() results in an allocation failure the ref count of the
device drops to 0 prior to the parent pointer being accessed.  Thus
resulting in use after free.

The bug bot AI correctly identified the fix.  Save a reference to the
parent pointer to be used to drop the parent reference regardless of the
outcome of device_add().