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The following is a list of general limitations and known issues of the various components of this Mellanox EN for Linux release.

For the list of old known issues, please refer to Mellanox EN Archived Known Issues file at:

Internal Reference NumberIssue


Description: Running 'ip link show' command over RHEL8.5 using ConnectX-3 with VFs will print "Truncated VFs" to the screen.

Workaround: Use the following OFED IP link command: /opt/mellanox/iproute2/sbin/ip link show

Keywords: IP Link, Virtual Functions,  ConnectX-3

Discovered in Release: 4.9-


Description: On Sles15Sp3, MFT restart does not work.

Workaround: Install MFT manually from

Keywords: MFT

Discovered in Release: 4.9-


Description: When upgrading MLNX_OFED from 4.9-4 to 5.4-2 GA using Yum installation, the installation fails due to ibutils.

Workaround: Before the upgrade, remove ibutils manually (and the metapackage with it) using the following command: yum remove ibutils

Keywords: Installation, ibutils

Discovered in Release: 4.9-


Description: On rare occasion, registering a device (ib_register_device()) and loading modules in parallel in this case (ib_cm) , a racing condition may occur which would stop ib_cm from loading properly. 

Workaround: Add modprobe.d rules to force the ib_cm driver to load before the mlx4_ib and mlx5_ib drivers:
install mlx4_ib { /sbin/modprobe ib_cm; /sbin/modprobe -ignore-install mlx4_ib $CMDLINE_OPTS; }
install mlx5_ib { /sbin/modprobe ib_cm; /sbin/modprobe —ignore-install mlx5_ib $CMDLINE_OPTS; }

Keywords: ib_core, Racing Condition

Discovered in Release: 4.9-

2175959Description: In rare cases where driver unload fails, the following message may appear: "rmmod: ERROR: Module mlx_compat is in use by: mdev vfio_mdev ib_core ib_uverbs".

Workaround: Remove “mdev vfio_mdev ib_core ib_uverbs” before restart driver.

Keywords: Installation

Discovered in Release: 4.9-

2636998Description: When using Debian or Ubuntu operating systems, installing MLNX_OFED with mlnxofedinstall and then proceeding to upgrade with a package manager (apt), the mlnx-rdma-core-dkms package remains installed and fails to rebuild. 

Workaround: Before upgrade, remove mlnx-rdma-rxe-dkms: dpkg --purge mlnx-rdma-rxe-dkms

Keywords: Upgrade, Debian, Ubuntu, mlnx-rdma-core-dkms

Discovered in Release: 4.9-

2635628Description: openibd should be started manually after reboot on EulerOS2.0sp9 OS.

Workaround: Start openibd using "/etc/init.d/openibd start"

Keywords: openibd, EulerOS2.0sp9

Discovered in Release: 4.9-

2338121Description: UCX will not work while running with upstream-libs if librdmacm is not installed.

Workaround: Install rdmacm or disable VMC (-x HCOLL_MCAST=^vmc).

Keywords: RDMA

Discovered in Release: 4.9-

2440042Description: Using ODP in this version may cause failures.

Workaround: To use ODP with ConnectX-4 and above, it is recommended to use MLNX_OFED version 5.2 and above.

Keywords: ar_mgr; dump_pr; upgrade; installation

Discovered in Release: 4.9-


Description: XDP is not supported over ConnectX-3 and ConnectX-3 Pro adapter cards.

Workaround: N/A
Keywords: XDP, ConnectX-3

Discovered in Release: 4.9-


Description: On ConnectX-3 and ConnectX-3 Pro adapter cards, no traffic runs between VLANs of any type over VLAN of type ctag (protocol 802.1Q).
Workaround: N/A
Keywords: ConnectX-3, VLAN

Discovered in Release: 4.9-


Description: On ConnectX-3 and ConnectX-3 Pro adapter cards, driver might hang when found under the following conditions, collectively:

  • OS kernel is older than 4.10
  • Interface is down
  • CONFIG_NET_RX_BUSY_POLL parameter is set
  • netdev_ops.ndo_busy_poll is defined
Workaround: N/A
Keywords: ConnectX-3

Discovered in Release: 4.9-


Description: MLNX_LIBS provider packages, such as libmlx5, cannot be installed simultaneously with ibverbs-providers distribution package when working with Ubuntu and Debian OSs.

Workaround: Before installing MLNX_OFED of type MLNX_LIBS, make sure that ibverbs-providers package is not installed.
Keywords: MLNX_LIBS, libmlx5, ibverbs-providers, Debian, Ubuntu

Discovered in Release: 4.9-


Description: MLNX_OFED includes several python tools, such as mlnx_qos, which rely on python modules included in the same package. On Ubuntu 20.04 OS, those are installed into a directory that is not in python modules search path.

Workaround: Link the python module to a directory in the python modules search path by running:

ln -s `dpkg -L mlnx-ofed-kernel-utils | grep 'site-.*py$'` /usr/lib/python3/dist-packages/
Keywords: mlnx_qos, Ubuntu

Discovered in Release: 4.9-


Description: hns_roce warning messages will appear in the dmesg after reboot on Euler2 SP3 OSs.
Workaround: N/A
Keywords: hns_roce, dmesg, Euler

Discovered in Release: 4.9-


Description: On kernels 4.10-4.14, when Geneve tunnel's remote endpoint is defined using IPv6, packets larger than MTU are not fragmented, resulting in no traffic sent.

Workaround: Define geneve tunnel's remote endpoint using IPv4. 
Keywords: Kernel, Geneve, IPv4, IPv6, MTU, fragmentation

Discovered in Release: 4.9-


Description: Multiple driver restarts may cause a stress and result in mlx5 commands check error message in the log.
Workaround: N/A
Keywords: Driver restart, syndrome, error message

Discovered in Release: 4.9-


Description: Ethtool --show-fec/--get-fec are not supported over ConnectX-6 and ConnectX-6 Dx adapter cards.
Workaround: N/A
Keywords: Ethtool, ConnectX-6 Dx

Discovered in Release: 4.9-


Description: IPsec crypto offloads does not work when ESN is enabled.
Workaround: N/A
Keywords: IPsec, ESN

Discovered in Release: 4.9-


Description: A kernel panic may occur over RH8.0-4.18.0-80.el8.x86_64 OS when opening kTLS offload connection due to a bug in kernel TLS stack.
Workaround: N/A
Keywords: TLS offload, mlx5e

Discovered in Release: 4.9-


Description: A Kernel panic may occur over Ubuntu19.04-5.0.0-38-generic OS when opening kTLS offload connection due to a bug in the Kernel TLS stack.
Workaround: N/A
Keywords: TLS offload, mlx5e

Discovered in Release: 4.9-


Description: Relaxed ordering memory regions are not supported when working with CAPI. Registering memory region with relaxed ordering while CAPI enabled will result in a registration failure.
Workaround: N/A
Keywords: Relaxed ordering, memory region, MR, CAPI

Discovered in Release: 4.9-


Description: The content of file /sys/class/net/<NETIF>/statistics/multicast may be out of date and may display values lower than the real values.
Workaround: Run ethtool -S <NETIF> to show the actual multicast counters and to update the content of file /sys/class/net/<NETIF>/statistics/multicast.
Keywords: Multicast counters

Discovered in Release: 4.9-


Description: An internal error might take place in the firmware when performing any of the following in VF LAG mode, when at least one VF of either PF is still bound/attached to a VM.

  1. Removing PF from the bond (using ifdown, ip link or any other function)
  2. Attempting to disable SR-IOV
Workaround: N/A
Keywords: VF LAG, binding, firmware, FW, PF, SR-IOV

Discovered in Release: 4.9-


Description: When running in a large scale in VF-LAG mode, bandwidth may be unstable.
Workaround: N/A
Keywords: VF LAG

Discovered in Release: 4.9-


Description: When working with OSs with Kernel v4.10, bonding module does not allow setting MTUs larger than 1500 on a bonding interface.
Workaround: Upgrade your Kernel version to v4.11 or above.
Keywords: Bonding, MTU, Kernel

Discovered in Release: 4.9-


Description: Libibverbs dependencies are removed during OFED installation, requiring manual installation of libraries that OFED does not reinstall.
Workaround: Manually install missing packages.
Keywords: libibverbs, installation

Discovered in Release: 4.9-


Description: Devlink health dumps are not supported on kernels lower than v5.3.
Workaround: N/A
Keywords: Devlink, health report, dump

Discovered in Release: 4.9-


Description: When changing the Trust mode to DSCP, there is an interval between the change taking effect in the hardware and updating the inline mode of the SQ in the driver. If any traffic is transmitted during this interval, the driver will not inline enough headers, resulting in a CQE error in the NIC. 

Workaround: Set the interface down, change the trust mode, then bring the interface back up.

ip link set eth0 down
mlnx_qos -i eth0 --trust dscp
ip link set eth0 up
Keywords: DSCP, inline, SQ, CQE

Discovered in Release: 4.9-


Description: For kernels with connection tracking support, neigh update events are not supported, requiring users to have static ARPs to work with OVS and VxLAN.
Workaround: N/A
Keywords: VxLAN, VF LAG, neigh, ARP

Discovered in Release: 4.9-


Description: Userspace RoCE UD QPs are not supported over distributions such as SLES11 SP4 and RedHat 6.10 for which the netlink 3 libraries (libnl-3 and libnl-route3) are not available.

Workaround: N/A
Keywords: RoCE UD, QP, SLES, RedHat, RHEL, netlink

Discovered in Release: 4.9-


Description: The argparse module is installed by default in Python versions =>2.7 and >=3.2. In case an older Python version is used, the argparse module is not installed by default.
Workaround: Install the argparse module manually.
Keywords: Python, MFT, argparse, installation
Discovered in Release: 4.7-

Description: Installing MLNX_EN with --with-openvswitch flag requires manual removal of the existing Open vSwitch.
Workaround: N/A
Keywords: OVS, Open vSwitch, openvswitch
Discovered in Release: 4.7-

Description: When bond is created over VF netdevices in SwitchDev mode, the VF netdevice will be treated as representor netdevice. This will cause the mlx5_core driver to crash if it receives netdevice events related to bond device.

Workaround: Do not create bond over VF netdevices in SwitchDev mode.
Keywords: PF, VF, SwitchDev, netdevice, bonding
Discovered in Release: 4.7-
1979834Description: When running MLNX_EN on Kernel 4.10 with ConnectX-3/ConnectX-3 Pro NICs, deleting VxLAN may result in a crash.
Workaround: Upgrade the Kernel version to v4.14 to avoid the crash.
Keywords: Kernel, OS, ConnectX-3, VxLAN
Discovered in Release: 4.7-
1997230Description: Running mlxfwreset or unloading mlx5_core module while contrak flows are offloaded may cause a call trace in the kernel.
Workaround: Stop OVS service before calling mlxfwreset or unloading mlx5_core module.
Keywords: Contrak, ASAP, OVS, mlxfwrest, unload
Discovered in Release: 4.7-
1955352Description: Moving 2 ports to SwitchDev mode in parallel is not supported.
Workaround: N/A
Keywords: ASAP, SwitchDev
Discovered in Release: 4.7-

Description: ib_core unload may fail on Ubuntu 18.04.2 OS with the following error message:

"Module ib_core is in use"

Workaround: Stop ibacm.socket using the following commands:

systemctl stop ibacm.socket

systemctl disable ibacm.socket

Keywords: ib_core, Ubuntu, ibacm
Discovered in Release: 4.7-
1979958Description: VxLAN IPv6 offload is not supported over CentOS/RHEL v7.2 OSs.
Workaround: N/A
Keywords: Tunnel, VXLAN, ASAP, IPv6
Discovered in Release: 4.7-
1980884Description: Setting VF VLAN, state and spoofchk using ip link tool is not supported in SwitchDev mode.
Workaround: N/A
Keywords: ASAP, ip tool, VF, SwitchDev
Discovered in Release: 4.7-
1991710Description: PRIO_TAG_REQUIRED_EN configuration is not supported and may cause call trace.
Workaround: N/A
Keywords: ASAP, PRIO_TAG, mstconfig
Discovered in Release: 4.7-

Description: With HW offloading in SR-IOV SwitchDev mode, the fragmented ICMP echo request/reply packets (with length larger than MTU) do not function properly. The correct behavior is for the fragments to miss the offloading flow and go to the slow path. However, the current behavior is as follows.

  • Ingress (to the VM): All echo request fragments miss the corresponding offloading flow, but all echo reply fragments hit the corresponding offloading flow
  • Egress (from the VM): The first fragment still hits the corresponding offloading flow, and the subsequent fragments miss the corresponding offloading flow
Workaround: N/A
Keywords: HW offloading, SR-IOV, SwitchDev, ICMP, VM, virtualization
Discovered in Release: 4.7-
1939719Description: Running openibd restart after the installation of MLNX_EN on SLES12 SP5 and SLES15 SP1 OSs with the latest Kernel (v4.12.14) will result in an error that the modules do not belong to that Kernel. This is due to the fact that the module installed by MLNX_EN is incompatible with new Kernel's module.

Workaround: Rebuild the Kernel modules by rerunning the ./install installation command using the following additional options:

--add-kernel-support --skip-repo

Keywords: SLES, operating system, OS, installation, Kernel, module
Discovered in Release: 4.7-
1969580Description: RHEL 6.10 OS is not supported in SR-IOV mode.
Workaround: N/A
Keywords: RHEL, RedHat, OS, operating system, SR-IOV, virtualization
Discovered in Release: 4.7-
1919335Description: On SLES 11 SP4, RedHat 6.9 and 6.10 OSs, on hosts where OpenSM is running, the low-level driver's internal error reset flow will cause a kernel crash when OpenSM is killed (after the reset occurs). This is due to a bug in these kernels where opening the umad device (by OpenSM) does not take a reference count on the underlying device.
Workaround: Run OpenSM on a host with a more recent Kernel.
Keywords: SLES, RedHat, CR-Dump, OpenSM
Discovered in Release: 4.7-
1916029Description: When the firmware response time to commands becomes very long, some commands fail upon timeout. The driver may then trigger a timeout completion on the wrong entry, leading to a NULL pointer call trace.
Workaround: N/A
Keywords: Firmware, timeout, NULL
Discovered in Release: 4.7-
1967866Description: Enabling ECMP offload requires the VFs to be unbound and VMs to be shut down.
Workaround: N/A
Keywords: ECMP, Multipath, ASAP2
Discovered in Release: 4.7-

Description: When using mlx5dv_dr API for flow creation, for flows which execute the "encapsulation" action or "push vlan" action, metadata C registers will be reset to zero.
Workaround: Use the both actions at the end of the flow process.
Keywords: Flow steering
Discovered in Release: 4.7-

Description: When the firmware response time to commands becomes very long, some commands fail upon timeout. The driver may then trigger a timeout completion on the wrong entry, leading to a NULL pointer call trace.
Workaround: N/A
Keywords: Firmware, timeout, NULL
Discovered in Release: 4.7-

Description: On Ubuntu, Debian and RedHat 8 and above OSS, parsing the mfa2 file using the mstarchive might result in a segmentation fault. 
Workaround: Use mlxarchive to parse the mfa2 file instead. 
Keywords: MFT, mfa2, mstarchive, mlxarchive, Ubuntu, Debian, RedHat, operating system
Discovered in Release: 4.7-

Description: MLNX_EN installation over SLES15 SP1 ARM OSs fails unless --add-kernel-support flag is added to the installation command.

Workaround: N/A
Keywords: SLES, installation
Discovered in Release: 4.7-

Description: MLNX_EN does not support XDP features on RedHat 7 OS, despite the declared support by RedHat.

Workaround: N/A
Keywords: XDP, RedHat
Discovered in Release: 4.7-

Description: Kernel support limitations in the current MLNX_EN version:

  • SwitchDev is only supported on Kernel 4.14 and above, and on RedHat/CentOS 7.4, 7.5 and 7.6.
  • SR-IOV is only supported on Kernel 4.3 and above, and on RedHat/CentOS 7.4, 7.5, 7.6 and 7.7.
Workaround: N/A
Keywords: SwitchDev, ASAP, Kernel , SR-IOV, RedHat
Discovered in Release: 4.7-

Description: mlnx_tune script does not support python3 interpreter.
Workaround: Run mlnx_tune with python2 interpreter only.
Keywords: mlnx_tune, python3, python2
Discovered in Release: 4.7-

Description: MLNX_EN installation on XenServer OSs requires using the -u flag.
Workaround: N/A
Keywords: Installation, XenServer, OS, operating system
Discovered in Release: 4.6-

Description: A bonding bug found in Kernels 4.12 and 4.13 may cause a slave to become permanently stuck in BOND_LINK_FAIL state. As a result, the following message may appear in dmesg:

bond: link status down for interface eth1, disabling it in 100 ms

Workaround: N/A
Keywords: Bonding, slave
Discovered in Release: 4.6-

Description: Installing RHEL 7.6 OSs platform x86_64 and RHEL 7.6 ALT OSs platform PPCLE using YUM is not supported.

Workaround: Install these OSs using the install script.
Keywords: RHEL, RedHat, YUM, OS, operating system
Discovered in Release: 4.6-

Description: Ubuntu v16.04.05 and v16.04.05 OSs can only be used with Kernels of version 4.4.0-143 or below.
Workaround: N/A
Keywords: Ubuntu, Kernel, OS
Discovered in Release: 4.6-

Description: Uninstalling MLNX_EN automatically results in the uninstallation of several libraries that are included in the MLNX_EN package, such as InfiniBand-related libraries.
Workaround: If these libraries are required, reinstall them using the local package manager (yum/dnf).
Keywords: MLNX_EN libraries
Discovered in Release: 4.6-

Description: Due to changes in libraries, MFT v4.11.0 and below are not forward compatible with MLNX_EN v4.6- and above.

Therefore, with MLNX_EN v4.6- and above, it is recommended to use MFT v4.12.0 and above.

Workaround: N/A
Keywords: MFT compatible
Discovered in Release: 4.6-

Description: On ConnectX-4 HCAs, GID index for RoCE v2 is inconsistent when toggling between enabled and disabled interface modes.
Workaround: N/A
Keywords: RoCE v2, GID
Discovered in Release: 4.6-

Description: MLNX_EN v4.6 YUM and Zypper installations fail on RHEL8.0, SLES15.0 and PPCLE OSs.
Workaround: N/A
Keywords: YUM, Zypper, installation, RHEL, RedHat, SLES, PPCLE
Discovered in Release: 4.6-

Description: On kernels 4.10-4.14, MTUs larger than 1500 cannot be set for a GRE interface with any driver (IPv4 or IPv6).
Workaround: Upgrade your kernel to any version higher than v4.14.
Keywords: Fedora 27, gretap, ip_gre, ip_tunnel, ip6_gre, ip6_tunnel
Discovered in Release: 4.6-

Description: Driver reload takes several minutes when a large number of VFs exists.
Workaround: N/A
Keywords: VF, SR-IOV
Discovered in Release: 4.6-

Description: Cannot set max Tx rate for VFs from the ARM.
Workaround: N/A
Keywords: Host control, max Tx rate
Discovered in Release: 4.6-

Description: Software counters not working for representor net devices.
Workaround: N/A
Keywords: mlx5, counters, representors
Discovered in Release: 4.6-

Description: Running heavy traffic (such as 'ping flood') while bringing up and down other mlx5 interfaces may result in “INFO: rcu_preempt dectected stalls on CPUS/tasks:” call traces.
Workaround: N/A
Keywords: mlx5
Discovered in Release: 4.6-

Description: Get/Set Forward Error Correction FEC configuration is not supported on ConnectX-6 HCAs with 200Gbps speed rate.
Workaround: N/A
Keywords: Forward Error Correction, FEC, 200Gbps
Discovered in Release: 4.6-

Description: Mellanox Firmware Tools (MFT) package is missing from Ubuntu v18.04.2 OS.
Workaround: Manually install MFT.
Keywords: MFT, Ubuntu, operating system
Discovered in Release: 4.6-

Description: On ConnectX-3 and ConnectX-3 Pro HCAs, CR-Dump poll is not supported using sysfs commands.
Workaround: If supported in your Kernel, use the devlink tool as an alternative to sysfs to achieve CR-Dump support.
Keywords: mlx4, devlink, CR-Dump
Discovered in Release: 4.6-

Description: On ConnectX-6 HCAs and above, an attempt to configure advertisement (any bitmap) will result in advertising the whole capabilities.
Workaround: N/A
Keywords: 200Gmbps, advertisement, Ethtool
Discovered in Release: 4.6-


Description: GID entries referenced to by a certain user application cannot be deleted while that user application is running.

Workaround: N/A

Keywords: RoCE, GID

Discovered in Release: 4.5-


Description: Attempting to allocate an excessive number of VFs per PF in operating systems with kernel versions below v4.15 might fail due to a known issue in the Kernel.

Workaround: Make sure to update the Kernel version to v4.15 or above.

Keywords: VF, PF, IOMMU, Kernel, OS

Discovered in Release: 4.5-


Description: On SLES 12 SP1 OSs, a kernel tracepoint issue may cause undefined behavior when inserting a kernel module with a wrong parameter.

Workaround: N/A

Keywords: mlx5 driver, SLES 12 SP1

Discovered in Release: 4.5-


Description: When using ConnectX-5 with LRO over PPC systems, the HCA might experience back pressure due to delayed PCI Write operations. In this case, bandwidth might drop from line-rate to ~35Gb/s. Packet loss or pause frames might also be observed.

Workaround: Look for an indication of PCI back pressure (“outbound_pci_stalled_wr” counter in ethtools advancing). Disabling LRO helps reduce the back pressure and its effects.

Keywords: Flow Control, LRO

Discovered in Release: 4.4-


Description: On RHEL v7.3, 7.4 and 7.5 OSs, setting IPv4-IP-forwarding will turn off LRO on existing interfaces. Turning LRO back on manually using ethtool and adding a VLAN interface may cause a warning call trace.

Workaround: Make sure IPv4-IP-forwarding and LRO are not turned on at the same time.

Keywords: IPv4 forwarding, LRO

Discovered in Release: 4.4-


Description: Software reset may result in an order inversion of interface names.

Workaround: Restart the driver to re-set the order.

Keywords: Software reset

Discovered in Release: 4.4-


Description: Retpoline support in GCC causes an increase in CPU utilization, which results in IP forwarding’s 15% performance drop.

Workaround: N/A

Keywords: Retpoline, GCC, CPU, IP forwarding, Spectre attack

Discovered in Release: 4.4-


Description: MLNX_EN cannot be installed on SLES 15 OSs using Zypper repository.

Workaround: Install MLNX_EN using the standard installation script instead of Zypper repository.

Keywords: Installation, SLES, Zypper

Discovered in Release: 4.4-


Description: When working with ConnectX-4/ConnectX-5 HCAs on PPC systems with Hardware LRO and Adaptive Rx support, bandwidth drops from full wire speed (FWS) to ~60Gb/s.

Workaround: Make sure to disable Adaptive Rx when enabling Hardware LRO: ethtool -C <interface> adaptive-rx off

ethtool -C <interface> rx-usecs 8 rx-frames 128

Keywords: Hardware LRO, Adaptive Rx, PPC

Discovered in Release: 4.3-


Description: NVMEoF protocol does not support LBA format with non-zero metadata size. Therefore, NVMe namespace configured to LBA format with metadata size bigger than 0 will cause Enhanced Error Handling (EEH) in PowerPC systems.

Workaround: Configure the NVMe namespace to use LBA format with zero sized metadata.

Keywords: NVMEoF, PowerPC, EEH

Discovered in Release: 4.3-


Description: In switchdev mode default configuration, stateless offloads/steering based on inner headers is not supported.

Workaround: To enable stateless offloads/steering based on inner headers, disable encap by running:

devlink dev eswitch show pci/0000:83:00.1 encap disable

Or, in case devlink is not supported by the kernel, run:

echo none > /sys/kernel/debug/mlx5/<BDF>/compat/encap

Note: This is a hardware-related limitation.

Keywords: switchdev, stateless offload, steering

Discovered in Release: 4.3-


Description: When setting a non-default IPv6 link local address or an address that is not based on the device MAC, connection establishments over RoCEv2 might fail.

Workaround: N/A

Keywords: IPV6, RoCE, link local address

Discovered in Release: 4.3-


Description: In RoCE LAG mode, when running ibdev2netdev -v , the port state of the second port of the mlx4_0 IB device will read “NA” since this IB device does not have a second port.

Workaround: N/A

Keywords: mlx4, RoCE LAG, ibdev2netdev, bonding

Discovered in Release: 4.3-


Description: Number of MSI-X that can be allocated for VFs and PFs in total is limited to 2300 on Power9 platforms.

Workaround: N/A

Keywords: MSI-X, VF, PF, PPC, SR-IOV

Discovered in Release: 4.3-


Description: Firmware reset might cause Enhanced Error Handling (EEH) on Power7 platforms.

Workaround: N/A

Keywords: EEH, PPC

Discovered in Release: 4.3-


Description: On Fedora 20 operating systems, driver load fails with an error message such as: “ [185.262460] kmem_cache_sanity_check (fs_ftes_0000:00:06.0): Cache name already exists. ”

This is caused by SLUB allocators grouping multiple slab kmem_cache_create into one slab cache alias to save memory and increase cache hotness. This results in the slab name to be considered stale.

Workaround: Upgrade the kernel version to kernel-3.19.8-100.fc20.x86_64.

Note that after rebooting to the new kernel, you will need to rebuild 
MLNX_EN against the new kernel version.

Keywords: Fedora, driver load

Discovered in Release: 4.3-


Description: When running perftest (ib_send_bw, ib_write_bw, etc.) in rdma-cm mode, the resp_cqe_error counter under /sys/class/infiniband/mlx5_0/ports/1/hw_counters/resp_cqe_error might increase. This behavior is expected and it is a result of receive WQEs that were not consumed.

Workaround: N/A

Keywords: perftest, RDMA CM, mlx5

Discovered in Release: 4.3-


Description: Configuring SR-IOV after disabling RoCE LAG using sysfs (/sys/bus/pci/drivers/mlx5_core/<bdf>/roce_lag_enable) might result in RoCE LAG being enabled again in case SR-IOV configuration fails.

Workaround: Make sure to disable RoCE LAG once again.

Keywords: RoCE LAG, SR-IOV

Discovered in Release: 4.3-


Description: On RHEL7.4, due to an OS issue introduced in kmod package version 20-15.el7_4.6, parsing the depmod configuration files will fail, resulting in either of the following issues:

  • Driver restart failure prompting an error message, such as: “ ERROR: Module mlx5_core belong to kernel which is not a part of MLNX_EN, skipping... ”
  • nvmet_rdma kernel module dysfunction, despite installing MLNX_EN using the "--with-nvmf " option. An error message, such as: “ nvmet_rdma: unknown parameter 'offload_mem_start' ignored ” will be seen in dmesg output

Workaround: Go to RedHat webpage to upgrade the kmod package version.

Keywords: driver restart, kmod, kmp, nvmf, nvmet_rdma

Discovered in Release: 4.2-


Description: Packet Size (Actual Packet MTU) limitation for IPsec offload on Innova IPsec adapter cards: The current offload implementation does not support IP fragmentation. The original packet size should be such that it does not exceed the interface's MTU size after the ESP transformation (encryption of the original IP packet which increases its length) and the headers (outer IP header) are added:

  • Inner IP packet size <= I/F MTU - ESP additions (20) - outer_IP (20) - fragmentation issue reserved length (56)
  • Inner IP packet size <= I/F MTU - 96

This mostly affects forwarded traffic into smaller MTU, as well as UDP traffic. TCP does PMTU discovery by default and clamps the MSS accordingly.

Workaround: N/A

Keywords: Innova IPsec, MTU

Discovered in Release: 4.2-


Description: No LLC/SNAP support on Innova IPsec adapter cards.

Workaround: N/A

Keywords: Innova IPsec, LLC/SNAP

Discovered in Release: 4.2-


Description: No support for FEC on Innova IPsec adapter cards. When using switches, there may be a need to change its configuration.

Workaround: N/A

Keywords: Innova IPsec, FEC

Discovered in Release: 4.2-


Description: Heavy traffic may cause SYN flooding when using Innova IPsec adapter cards.

Workaround: N/A

Keywords: Innova IPsec, SYN flooding

Discovered in Release: 4.2-


Description: Priority Based Flow Control is not supported on Innova IPsec adapter cards.

Workaround: N/A

Keywords: Innova IPsec, Priority Based Flow Control

Discovered in Release: 4.2-


Description: Pause configuration is not supported when using Innova IPsec adapter cards. Default pause is global pause (enabled).

Workaround: N/A

Keywords: Innova IPsec, Global pause

Discovered in Release: 4.2-


Description: Connecting and disconnecting a cable several times may cause a link up failure when using Innova IPsec adapter cards.

Workaround: N/A

Keywords: Innova IPsec, Cable, link up

Discovered in Release: 4.2-


Description: On Innova IPsec adapter cards, supported MTU is between 512 and 2012 bytes. Setting MTU values outside this range might fail or might cause traffic loss.

Workaround: Set MTU between 512 and 2012 bytes.

Keywords: Innova IPsec, MTU

Discovered in Release: 4.2-


Description: On kernel versions 4.10-4.13, when resetting sriov_numvfs to 0 on PowerPC systems, the following dmesg warning will appear:

mlx5_core <BDF>: can't update enabled VF BAR0

Workaround: Reboot the system to reset sriov_numvfs value.

Keywords: SR-IOV, numvfs

Discovered in Release: 4.2-


Description: In old kernel versions, such as Ubuntu 14.04 and RedHat 7.1, VXLAN interface does not reply to ARP requests for a MAC address that exists in its own ARP table. This issue was fixed in the following newer kernel versions: Ubuntu 16.04 and RedHat 7.3.

Workaround: N/A

Keywords: ARP, VXLAN

Discovered in Release: 4.2-


Description: When using kernel versions older than version 4.7 with IOMMU enabled, performance degradations and logical issues (such as soft lockup) might occur upon high load of traffic. This is caused due to the fact that IOMMU IOVA allocations are centralized, requiring many synchronization operations and high locking overhead amongst CPUs.

Workaround: Use kernel v4.7 or above, or a backported kernel that includes the following patches:

  • 2aac630429d9 iommu/vt-d: change intel-iommu to use IOVA frame numbers
  • 9257b4a206fc iommu/iova: introduce per-cpu caching to iova allocation
  • 22e2f9fa63b0 iommu/vt-d: Use per-cpu IOVA caching

Keywords: IOMMU, soft lockup

Discovered in Release: 4.2-


Description: On 64k page size setups, DMA memory might run out when trying to increase the ring size/number of channels.

Workaround: Reduce the ring size/number of channels.

Keywords: DMA, 64K page

Discovered in Release: 4.2-


Description: When configuring VF VST, VLAN-tagged outgoing packets will be dropped in case of ConnectX-4 HCAs. In case of ConnectX-5 HCAs, VLAN-tagged outgoing packets will have another VLAN tag inserted.

Workaround: N/A

Keywords: VST

Discovered in Release: 4.2-


Description: On Passthrough/VM machines with relatively old QEMU and libvirtd,

CMD timeout might occur upon driver load.

After timeout, no other commands will be completed and all driver operations will be stuck.

Workaround: Upgrade the QEMU and libvirtd on the KVM server.

Tested with (Ubuntu 16.10) are the following versions:

  • libvirt 2.1.0
  • QEMU 2.6.1

Keywords: QEMU

Discovered in Release: 4.2-


Description: Using dm-multipath for High Availability on top of NVMEoF block devices must be done with “directio” path checker.

Workaround: N/A

Keywords: NVMEoF

Discovered in Release: 4.2-


Description: RedHat v7.3 PPCLE and v7.4 PPCLE operating systems do not support KVM qemu out of the box. The following error message will appear when attempting to run virt-install to create new VMs:

Cant find qemu-kvm packge to install

Workaround: Acquire the following rpms from the beta version of 7.4ALT to 7.3/7.4 PPCLE (in the same order):

  • qemu-img-.el7a.ppc64le.rpm
  • qemu-kvm-common-.el7a.ppc64le.rpm
  • qemu-kvm-.el7a.ppc64le.rpm

Keywords: Virtualization, PPC, Power8, KVM, RedHat, PPC64LE

Discovered in Release: 4.2-


Description: A soft lockup in the CQ polling flow might occur when running very high stress on the GSI QP (RDMA-CM applications). This is a transient situation from which the driver will later recover.

Workaround: N/A

Keywords: RDMA-CM, GSI QP, CQ

Discovered in Release: 4.2-


Description: When working in RoCE LAG over kernel v3.10, a kernel crash might occur when unloading the driver as the Network Manager is running.

Workaround: Stop the Network Manager before unloading the driver and start it back once the driver unload is complete.

Keywords: RoCE LAG, network manager

Discovered in Release: 4.2-


Description: When setting VGT+, the maximal number of allowed VLAN IDs presented in the sysfs is 813 (up to the first 813).

Workaround: N/A

Keywords: VGT+

Discovered in Release: 4.2-


Description: Lustre support is limited to versions 2.9 and 2.10.

Workaround: N/A

Keywords: Lustre

Discovered in Release: 4.1-


Description: In kernels below v4.13, connection between NVMEoF host and target cannot be established in a hyper-threaded system with more than 1 socket.

Workaround: On the host side, connect to NVMEoF subsystem using --nr-io-queues <num_queues> flag.

Note that num_queues must be lower or equal to num_sockets multiplied with num_cores_per_socket.

Keywords: NVMEoF


Description: Enabling multiple namespaces per subsystem while using NVMEoF target offload is not supported.

Workaround: To enable more than one namespace, create a subsystem for each one.

Keywords: NVMEoF Target Offload, namespace


Description: Creating virtual functions on a device that is in LAG mode will destroy the LAG configuration. The boding device over the Ethernet NICs will continue to work as expected.

Workaround: N/A

Keywords: LAG, SR-IOV


Description: When node GUID of a device is set to zero (0000:0000:0000:0000), RDMA_CM user space application may crash.

Workaround: Set node GUID to a nonzero value.

Keywords: RDMA_CM


Description: New versions of iproute which support new kernel features may misbehave on old kernels that do not support these new features.

Workaround: N/A

Keywords: iproute


Description: When working on Xenserver hypervisor with SR-IOV enabled on it, make sure the following instructions are applied:

  1. Right after enabling SR-IOV, unbind all driver instances of the virtual functions from their PCI slots.
  2. It is not allowed to unbind PF driver instance while having active VFs.

Workaround: N/A

Keywords: SR-IOV


Description: When using ConnectX-5 adapter cards, the following error might be printed to dmesg, indicating temporary lack of DMA pages:

“mlx5_core ... give_pages:289:(pid x): Y pages alloc time exceeded the max permitted duration

mlx5_core ... page_notify_fail:263:(pid x): Page allocation failure notification on func_id(z) sent to fw

mlx5_core ... pages_work_handler:471:(pid x): give fail -12”

Example: This might happen when trying to open more than 64 VFs per port.

Workaround: N/A

Keywords: mlx5_core, DMA


Description: Performing some operations on the user end during reboot might cause call trace/panic, due to bugs found in the Linux kernel.

For example: Running get_vf_stats (via iptool) during reboot.

Workaround: N/A

Keywords: mlx5_core, reboot


Description: Mounting MLNX_EN to a path that contains special characters, such as parenthesis or spaces is not supported. For example, when mounting MLNX_EN to “/media/CDROM(vcd)/”, installation will fail and the following error message will be displayed:

# cd /media/CDROM\(vcd\)/

# ./install

sh: 1: Syntax error: "(" unexpected

Workaround: N/A

Keywords: Installation


Description: When offload traffic sniffer is on, the bandwidth could decrease up to 50%.

Workaround: N/A

Keywords: Offload Traffic Sniffer


Description: In ConnectX-3, when using a server with page size of 64K, the UAR BAR will become too small. This may cause one of the following issues:

  1. mlx4_core driver does not load.
  2. The mlx4_core driver does load, but calls to ibv_open_device may return ENOMEM errors.


  1. Add the following parameter in the firmware's ini file under [HCA] section: log2_uar_bar_megabytes = 7
  2. Re-burn the firmware with the new ini file.

Keywords: PPC


Description: On several OSs, setting a number of TC is not supported via the tc tool.

Workaround: Set the number of TC via the /sys/class/net/<interface>/qos/tc_num sysfs file.

Keywords: Ethernet, TC


Description: When setting IOMMU=ON, a severe performance degradation may occur due to a bug in IOMMU.

Workaround: Make sure the following patches are found in your kernel:

  • iommu/vt-d: Fix PASID table allocation
  • iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions

Note: These patches are already available in Ubuntu 16.04.02 and 17.04 OSs.

Keywords: Performance, IOMMU

Workaround: Upgrade the Kernel version to v4.14 to avoid the crash.