CVE-2025-38338 fs/nfs/read: fix double-unlock bug in nfs_return_empty_folio()

In the Linux kernel, the following vulnerability has been resolved: fs/nfs/read: fix double-unlock bug in nfsreturnemptyfolio Sometimes, when a file was read while it was being truncated by another NFS client, the kernel could deadlock because foliounlock was called twice, and the second call wou...