CVE-2026-98995 namespace: reset the old parent's ->overmount in mnt_change_mountpoint()

In the Linux kernel, the following vulnerability has been resolved: namespace: reset the old parent's -overmount in mntchangemountpoint umountmnt resets -overmount of the parent when it unmounts the mount that overmounts it. mntchangemountpoint doesn't. It moves the mount to its new parent and...