CVE-2026-89956 s390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects

In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: Fix missing lock required to access list of apmatrixmdev objects In order to traverse or add/remove apmatrixmdev objects in the matrixdev-mdevlist, the matrixdev-guestslock mutex must be held. There are two function...