CVE-2025-38691 pNFS: Fix uninited ptr deref in block/scsi layout

In the Linux kernel, the following vulnerability has been resolved: pNFS: Fix uninited ptr deref in block/scsi layout The error occurs on the third attempt to encode extents. When function exttreepreparecommit reallocates a larger buffer to retry encoding extents, the "layoutupdatepages" page arr...