CVE-2025-40212 nfsd: fix refcount leak in nfsd_set_fh_dentry()

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix refcount leak in nfsdsetfhdentry nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the various exported filesystems using LOOKUP requests from a known root filehandle. NFSv3 uses the MOUNT protocol ...