New Features and Changes in UEK R6U2

UEK R6U2 uses the 5.4.17-2102 version and build of the UEK R6 kernel, which includes security and bug fixes, as well as driver updates.

UEK R6U2 provides equivalent core kernel functionality to UEK R6, but is updated to the upstream mainline kernel v5.4.83 release tag and includes upstream LTS bug fixes, with additional patches to enhance existing functionality and provide some minor bug fixes and security improvements. Key changes are specific to functionality that is required for Oracle Database and other Oracle software.

Support for the vHost Data Path Acceleration (vDPA) framework, as well as Mellanox CX6-DX VDPA driver, has been added in this update. When utilized on a host, this feature provides for high-performance, Virtual I/O Device (VirtIO) acceleration. This functionality is implemented by the device's hardware, while preserving the ability to use standard VirtIO drivers on the virtual machines (VMs) that are running on the host.

This update provides fixes for most of the bugs that were present in the 5.9 kernel. Other notable NVMe improvements and changes that are introduced include the following:

• nvmet: ctrl model and ctrl-id is configurable through subsys attribute

  This change adds a new target subsys attribute that enables you to optionally specify a model name and a ctrl-did, which then is used in the nvmet_execute_identify_ctrl() function to complete the nvme_id_ctrl structure.

• nvme: hostid and hostnqn exposed through sysfs for fabrics controllers

  This change enables user space to connect with a custom hostid and hostnqn, which can be useful in certain cases. Note, however, that there is no way to determine what hostid is used to connect to a given controller.

• nvme-fc/nvmet-fc: FC-NVME-2 disconnect association support added

  This added support improves the error-handling framework for NVMe-FC and is enabled in the Emulex (lpfc) driver.

The following file system changes are implemented in UEK R6U2:

• Btrfs

  General upstream patches for security enhancements and bug fixes have been applied.

• CIFS

  General upstream bug fix patches have been applied. Notably, a fix was applied for an issue that resulted in a kernel panic when the CIFS module attempted a reconnect to a CIFS server that was unavailable.

• Ext4

  General upstream patches for security enhancements and bug fixes have been applied.

• NFS

  General upstream bug fixes and performance enhancements have been applied for NFS. Additionally, several fixes and improvements were applied for NFS v4.2 Server Side Copy functionality which remains available as a technical preview.

• OCFS2

  A fix was applied to better handle setting ACLs on the file system so that they are made effective immediately and any cached ACLs are reset.

• XFS

  General upstream patches for security enhancements and bug fixes have been applied.

Kernel improvements have been made in this release to boost IOPS (input/output operations per second) for a vhost SCSI device over dm-multipath.

Notable changes, fixes, and improvements include the following:

• Improved error handling for vhost-scsi to prevent SCSI commands from failing when a SCSI command times out in the guest OS.

• A fix to the vhost-scsi module's multiqueue support so that a single vhost-scsi device can execute up to 1024 commands over up to 128 virtqueues.

Several features are under investigation and ongoing development for release within UEK R6. The following features are available within UEK R6U2 as a technical preview.

• Core Scheduling

  Core scheduling is a feature enabled in the kernel to limit trusted tasks to run concurrently on CPU cores that share compute resources to help mitigate against certain categories of 'core shared cache' processor bugs that could cause data leakage and other related vulnerabilities. This feature has been enabled in UEK R6 since UEK R6U1 as a technical preview and is under active development.

• WireGuard

  WireGuard is a faster and more secure replacement for IPsec and OpenVPN. New networks are being built with modern cryptography from WireGuard rather than legacy technologies like IPsec and OpenVPN. WireGuard has been enabled as a technical preview in UEK R6 since UEK R6U1 and continues to be available as a technical preview in the current update release. Several improvements for WireGuard are included in this update release.

• NFS v4.2 Server Side Copy

  NFS v4.2 Server Side Copy functionality is back-ported from the upstream kernel and has been available in UEK R6 since UEK R6U1 as a technical preview. The server-side copy features provide mechanisms that allow an NFS client to copy file data on a server or between two servers without the data being transmitted back and forth over the network through the NFS client. Several improvements for this feature are included in this update release.

The Unbreakable Enterprise Kernel Release 6 supports a large number of hardware and devices. In close cooperation with hardware and storage vendors, Oracle has updated several device drivers from the versions in mainline Linux 5.4.

A complete list of the driver modules included in the latest update of UEK R6 along with version information is provided in the appendix at Driver Modules in Unbreakable Enterprise Kernel Release 6 (x86_64).

The following new features are noted in the drivers that are shipped with UEK R6U2:

• Broadcom Emulex LightPulse Fibre Channel SCSI driver

  The Broadcom Emulex LightPulse Fibre Channel SCSI driver, lpfc, is updated to version 12.8.0.5 with vendor supplied patches and bug fixes. Notably, a 256 Gb speed setting is enabled for SCSI Fibre Channel transport.

• LSI MPT Fusion SAS 3.0 Device driver

  The LSI MPT Fusion SAS 3.0 Device driver, mpt3sas, is updated to version 36.100.00.00 to include vendor supplied patches that bring the driver version in line with the upstream kernel release.

• QLogic Fibre Channel HBA driver

  The QLogic Fibre Channel HBA driver, qla2xxx is updated to version 10.02.00.103-k and includes a large number of vendor supplied patches to bring the driver version in line with the upstream kernel release.