Red Hat Enterprise Linux 7.4 for ARM - Release Notes

Updated -

Red Hat Enterprise Linux 7.4 for ARM introduces Red Hat Enterprise Linux 7.4 user space with an updated kernel. The new kernel version 4.11 is provided by the kernel-alt packages. The offering is distributed with other updated packages; most of the packages are standard Red Hat Enterprise Linux 7 Server RPMs.

Installation ISO images are available on the Customer Portal Downloads page.

For information about Red Hat Enterprise Linux 7.4 user space, see the Release Notes and other Red Hat Enterprise Linux 7 documentation.

The following packages are being distributed with this release:

  • binutils
  • elinks
  • iproute
  • js
  • kernel-alt
  • libproxy
  • mesa-private-llvm
  • mozjs17
  • oprofile
  • papi and libpfm
  • polkit
  • rdma-core
  • systemtap

The following packages are provided as Development Preview in this release:

  • libvirt (Optional channel)
  • qemu-kvm (Optional channel)

Note: KVM is a development preview (unsupported) on the 64-bit ARM architecture. Customers may contact Red Hat and describe their use case, which will be taken into consideration for a future release of Red Hat Enterprise Linux.

Kernel Configuration Changes

HW Enablement

  • Bluetooth (disabled)
  • WIRELESS (disabled)
  • CPU_IDLE (enabled)
  • GPIO_DWAPB (enabled)
  • I2C (enabled) - Designware, QUP, and XLP9XX
    • sensor support:
      • IIO drivers (disabled)
      • Accel sensors (disabled)
      • light + orientation + interrupt trigger (disabled)
  • Input driver
    • mouse, synaptics, rmi4
  • LED
    • Intel SS4200 (disabled)
  • Generic IRQ CHIP (enabled)
  • Hibernate (enabled)
  • Clock Source DATA (enabled)
  • Sound
    • OSS_CORE (disabled)
    • all SND drivers (disabled)
Networking Driver Support
  • Thunder2 driver (enabled)
  • Amazon (enabled)
  • Altera (disabled)
  • ARC (disabled)
  • Broadcom B44, BCMGENET, BNX2X_VLAN, CNIC (disabled)
  • Hisilicon (enabled)
  • cadence MACB (disabled)
  • Chelsio T3 (disabled)
  • Intel E1000 (disabled)
  • Mellanox (enabled)
  • myri10GE (disabled)
  • Qlogic - qla2xxx, netxen_nic, Qed, Qede (enabled)
  • Qualcomm - qcom_emac (enabled)
  • Broadcom - bcm7xxx (disabled)
Infiniband Support (enabled)
  • CXBG4, I40IW, MLX4, MLX5, IPOIB, IPOIB_CM, IPOIB_DEBUG, ISERT, SRP, SRPT (enabled)

Core Kernel Support

  • Schedule Imbalance (enabled)
  • 48 bit VA support (enabled)
  • tick cpu accounting (disabled)
  • Context Tracking (enabled)
  • RCU NOCB (enabled)
  • CGROUP-Hugetlb (enabled)
  • CRIU (enabled)
  • BPF_SYSCALL (disabled)
  • PERF_USE_VMALLOC (disabled)
  • HZ_100/HZ (enabled)
  • NO_HZ_IDLE (disabled)
  • NO_HZ_FULL (enabled)
  • BPF_EVENTS (disabled)
  • LZ4 compression (disabled)
  • BTREE (enabled)
  • CPUMASK_OFFSTACK (disabled)
  • DEBUG_INFO_DWARF4 (enabled)
  • SCHEDSTATS (enabled)
  • Striaght DEVMEM (disabled)
  • Transparent Hugepage (HTP) (enabled)
  • ZSMaLLOC_STAT, IDLE_PAGE_TRACKING(enabled)
  • PAGE_EXTENSION and PAGE_POISONING (disabled)
Networking Stack support
  • SLIP - (enabled)
  • JME (disabled)
  • IPVLAN (disabled)
  • BPF_JIT (disabled)
  • dccp (disabled)
  • [ipv4] NET_FOU, Diag, CDG, NV (disabled)
  • [ipv6] ILA (disabled), GRE (enabled)
  • MAC80211 (disabled)
  • netfilter _ conntrack (enabled)
Graphic/GPU Support
  • DRM_I2C_SIL64 (disabled)
  • TTY
    • serial_nonstandard, cyclades, synclinkmp, synclink_gt, N_HDLC, serial_8250_MID (enabled)
    • fbdev (enabled)
  • USB - PHY (disabled)
Storage Support
  • Block scsi request (enabled)
  • Block debugfs (enabled)
  • Block Multi-Queue PCI (enabled)
  • Block Multi-Queue VirtIO (enabled)
  • Block Multi-Queue IOSched_deadline (enabled)
  • MD Long Write -(disabled)
  • SCSI - ARCMSR, AM53C974, WD719x, BNX2X_FCOE, BNX2_ISCSI, ESAS2R (disabled)
  • SCSI - HISI_SAS (enabled)
  • SPI - QUP, SLP (enabled)
  • SSB (disabled)
File Systems
  • FS_DAX (enabled)
  • BTRFS (disabled)
  • Ceph (enabled)
  • DLM (disabled)
  • FSCAHE (disabled)
  • GFS2 (disabled)
  • Swap over NFS (disabled)
  • NFS-FSCACHE (enabled)
Virtualization and KVM Support
  • KVM_IRQCHIP, KVM_IRQ_ROUTING, KVM_MSI (enabled)
  • Virtio - noiommu (enabled)

Known Issues

NMI watchdog reports soft lockups under heavy CPU load

A kernel bug concerning a fairness issue when CPUs are competing for the global task lock, which happens in cases where many short-lived tasks are created, may cause processes to be killed. When this happens, the kernel ring buffer (dmesg) displays error messages similar to the following:

NMI watchdog: BUG: soft lockup - CPU#47 stuck for 44s! [stress-ng-sleep:9967]

The cause of the bug is unknown at the time of writing this document, and there is no available workaround. (BZ#1454844)

ipmitool communicates with BMC only when "IPMI_SI=no" on Cavium ThunderX

When starting ipmi.service with the systemctl command, the default configuration attempts to load the ipmi_si driver. On Cavium ThunderX systems, which do not have an IPMI SI device, ipmi.service incorrectly removes the ipmi_devintf driver. Consequently, the ipmitool utility in the kernel is not able to communicate with the Baseboard Management Controller (BMC).

To work around this problem, edit the /etc/sysconfig/ipmi file and set the IPMI_SI variable as follows:

IPMI_SI=no

Then, reboot the operating system if necessary. As a result, the correct drivers are loaded and ipmitool can communicate with BMC through the /dev/ipmi0 directory. (BZ#1448181)

Bug Fixes

Memory exhaustion causing OOM on the 64-bit ARM systems has been fixed when kdump or CMA features are enabled

On the 64-bit ARM systems with memory limited to <=1G, the crash kernel consumed about 512M of memory and the Contiguous Memory Allocator (CMA) took around 512M of the remaining memory, thus exhausting the system memory. Consequently, some user-space applications, such as Shared Memory in Linux (SHM)(/dev/shm), could cause the out-of-memory (OOM) conditions with the following error message:

Out of memory: Kill process 23474 (shm_open_23-1.r) score 0 or sacrifice child

With this update, the underlying kexec source code addressing the crash kernel and CMA has been fixed. As a result, the OOM conditions due to memory exhaustion no longer occur when dumping the kernel on systems with limited memory size. (BZ#1492799)

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18 Comments

The link to the beta on the download site seems broken (directed me to x86_64). Or does this require a specific entitlement?

Hello, can you try again please, and let me know if it's fine now? We believe it was just a hiccup, I can see the ARM downloads even when I'm not logged in so it should be accessible to anyone.

If it still redirects you back to x86_64, can you find ARM on the standard RHEL downloads page by picking "Red Hat Enterprise Linux for ARM 64" in the Product Variant drop-down?

No still does not work with the link in this article.

The link you provided in your answer also goes to the same place (and the dropdown does not have "Red Hat Enterprise Linux for ARM 64" in it.

If not logged in the link you provided goes to the login page.

I also do not see the "Red Hat Enterprise Linux for ARM 64" link from the Product Variant drop down. Can the drop down option be enabled, or some other link to the ARM download be made available?

Either the link is still broken or access has to be granted. I do not see any "RHEL7 for ARM"....only x86... Results are same using the standard RHEL downloads page in comments or URL given on original page.

I have the same issue, no ARM variants are available for download.

Hello all, Thank you for reporting this issue. The link changed with GA some other way than we expected at the time of Beta. I have fixed the link to the downloads page.

Hello, I found in https://access.redhat.com/articles/2048973

"You must have the necessary permissions to download installation images for 64-bit ARM from Red Hat Customer Portal. Unlike other types subscriptions, these permissions are not obtained directly from Red Hat - instead, your hardware vendor will provide you with a Registration Code, which you can use on your Red Hat account to gain access to Red Hat Enterprise Linux Server for ARM Development Preview in Downloads section of the Red Hat Customer Portal. The procedure below outlines the process of gaining access to ARM installation ISO images."

Does that mean I have to buy equipment from the vendor and get access registration code from vendor?

I ask because on my account download link still doesn't work.

Still not seeing anything on any customer accounts I manage.

Is it a CDN issue? Has anyone from Red Hat tested downloading from a standard customer account?

Link is broken. I don't see ARM ISO available for download.

I also have my sad face on as I was hoping to test drive the new ARM media. I tried asking for access almost a year ago and was asked to verify my vendor code. Raspberry Pi does not count apparently and I never obtained access. Meanwhile Fedora ARM works just fine..

https://arm.fedoraproject.org/

Is there an ETA for when the Hardware Compatability list for RHEL 7 on ARM will be updated?
https://hardware.redhat.com/RHELSA

Can anyone confirm if it's just ThunderX at this stage?

We are currently going through and resolving some we asset issues we've identified. Red Hat had historically released the "Red Hat Enterprise Linux Server for ARM Development Preview". This was used for our hardware partners to perform hardware enablement work of the latest system capabilities.

When we officially transitioned this to a supported effort and offering (https://www.redhat.com/en/blog/open-across-all-architectures-introducing-red-hat%E2%80%99s-multi-architecture-initiative) with "Red Hat Enterprise Linux for ARM" (Dropped the Server and Development Preview) it has caused some brand and asset confusion on product pages, download pages.

As we transition our technology partners that had leveraged the previous "RHEL for ARM Server Development Preview" to our official partner programs, these web assets will be cleaned and streamlined to align with the current, supported offering.

The link is still redirect to x86_64.

Red Hat Enterprise Linux for ARM is a separate offering from Red Hat than x86_64 or other architectures. It will require a separate subscription and entitlement. At this point in time, Red Hat is only offering RHEL for ARM in partnership and alignment with our Premier OEM Partners' hardware plans on certified hardware. We encourage you to contact your hardware vendor to discuss options for Arm architecture enablement in the enterprise.

Scott,

Who are your 'Premier OEM Partners' (HPE and Cavium?) and who is actually offering a ARM capable servers that provide access to the Red Hat ARM releases? Where is the supported/compatible hardware list (HCL)?

Why is aarch64 a separate offering? is there a reason for separating it?

At this point, we have jointly announced a solution with HPE and their Apollo 70 server: https://www.redhat.com/en/blog/red-hat-introduces-arm-server-support-red-hat-enterprise-linux. We continue to work with all OEMs that have plans to release Arm hardware to the enterprise, some of which are still under NDA and cannot be publicly disclosed. As embargoes are lifted, you will see more news from Red Hat and the Arm ecosystem in that regard.

We maintain an engineering relationship with all major SoCs (Cavium, Qualcomm, HiSilicon, etc), but our delivery model is aligned with OEMs that leverage those SoCs in their hardware offerings.

All RHEL architectures are, and have been, treated as separate SKUs and subscriptions/entitlements. We are treating AArch64 no differently than we do ppc64le or s390x in that regard.

The examples you give of ppc and s390x are both tied to a single manufacturer and are midrange/mainframe so understandably are licensed differently.

I believe aarch64 is more closely aligned with the IA64 (Itanium) model of distribution. From memory IA64 was provided under the same SKU as an alternative architecture for the same product. I still have acces to IA64 downloads under RHEL 5 (before support was dropped), and I haven't touched Itanium hardware in years.

Do customers need to purchase the Red Hat aarch64 licensing through the hardware OEM rather than through Red Hat?

Is it likely hardware like the following to be supported in future (based on components and HCL) or will the OEM require an agreement with Red Hat (understand they may be under NDA)?
https://www.avantek.co.uk/arm-server-h270-t70/

Or even:
http://www.asacomputers.com/Cavium-ThunderX-ARM.html

-edit- removed comment re: upstream