Microsoft Azure - Kernel panic related due to mlx5_core driver

This document (000021005) is provided subject to the disclaimer at the end of this document.


SUSE Linux Enterprise Server 12 - SP 4 - LTSS
SUSE Linux Enterprise Server 12 - SP 5
SUSE Linux Enterprise Server 15 - SP 1
SUSE Linux Enterprise Server 15 - SP 2
SUSE Linux Enterprise Server 15 - SP 3
SUSE Linux Enterprise Server 15 - SP 4

SUSE Linux Enterprise Server for SAP Applications 12 - SP 4 - ESPOS
SUSE Linux Enterprise Server for SAP Applications 12 - SP 5
SUSE Linux Enterprise Server for SAP Applications 15 - SP 1
SUSE Linux Enterprise Server for SAP Applications 15 - SP 2
SUSE Linux Enterprise Server for SAP Applications 15 - SP 3
SUSE Linux Enterprise Server for SAP Applications 15 - SP 4

Microsoft Azure


The used Microsoft Azure kernel module "mlx5_core" causes a kernel panic, the crash is triggered by Mellanox VF add/remove events.

Additional information and output from commands executed on SUSE Linux Enterprise Server for SAP Applications 15 Service Pack 4:
# dmesg

[20747.904589] hv_netvsc 00224882-00d1-0022-4882-00d100224882 eth0: Data path switched from VF: eth2
[20748.082681] hv_netvsc 00224882-00d1-0022-4882-00d100224882 eth0: VF unregistering: eth2
[20748.087866] mlx5_core f0a2:00:02.0 eth2 (unregistering): Disabling LRO, not supported in legacy RQ
[20749.938028] hv_netvsc 00224882-00d1-0022-4882-00d100224882 eth0: VF slot 1 removed
[20749.940727] pci_bus f0a2:00: busn_res: [bus 00] is released
[20750.661865] hv_netvsc 00224882-00d1-0022-4882-00d100224882 eth0: VF slot 1 added
[20750.662626] hv_pci edb08bf6-f0a2-48c9-9c9a-f120cb611ef5: PCI VMBus probing: Using version 0x10004
[20752.539511] hv_pci edb08bf6-f0a2-48c9-9c9a-f120cb611ef5: PCI host bridge to bus f0a2:00
[20752.541175] hv_netvsc 00224882-00d1-0022-4882-00d100224882 eth0: VF slot 1 removed
# modinfo mlx5_core

filename:       /lib/modules/5.14.21-150400.24.38-default/kernel/drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko.zst
license:        Dual BSD/GPL
description:    Mellanox 5th generation network adapters (ConnectX series) core driver
author:         Eli Cohen <>
suserelease:    SLE15-SP4
srcversion:     EA83021FF5434929ED33F2F
alias:          auxiliary:mlx5_core.eth
alias:          pci:v000015B3d0000A2DFsv*sd*bc*sc*i*
alias:          pci:v000015B3d0000A2DCsv*sd*bc*sc*i*
alias:          pci:v000015B3d0000A2D6sv*sd*bc*sc*i*
alias:          pci:v000015B3d0000A2D3sv*sd*bc*sc*i*
alias:          pci:v000015B3d0000A2D2sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001023sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001021sv*sd*bc*sc*i*
alias:          pci:v000015B3d0000101Fsv*sd*bc*sc*i*
alias:          pci:v000015B3d0000101Esv*sd*bc*sc*i*
alias:          pci:v000015B3d0000101Dsv*sd*bc*sc*i*
alias:          pci:v000015B3d0000101Csv*sd*bc*sc*i*
alias:          pci:v000015B3d0000101Bsv*sd*bc*sc*i*
alias:          pci:v000015B3d0000101Asv*sd*bc*sc*i*
alias:          pci:v000015B3d00001019sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001018sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001017sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001016sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001015sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001014sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001013sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001012sv*sd*bc*sc*i*
alias:          pci:v000015B3d00001011sv*sd*bc*sc*i*
alias:          auxiliary:mlx5_core.eth-rep
alias:          auxiliary:mlx5_core.sf
depends:        tls,pci-hyperv-intf,mlxfw,psample
supported:      yes
retpoline:      Y
intree:         Y
name:           mlx5_core
vermagic:       5.14.21-150400.24.38-default SMP preempt mod_unload modversions 
sig_id:         PKCS#7
signer:         SUSE Linux Enterprise Secure Boot CA
sig_key:        ED:87:85:B7:8F:FC:12:7F
sig_hashalgo:   sha256
signature:      BE:84:24:0C:CA:94:E6:0D:36:29:D1:13:79:BC:E5:54:3B:85:94:A0:
parm:           debug_mask:debug mask: 1 = dump cmd data, 2 = dump cmd exec time, 3 = both. Default=0 (uint)
parm:           prof_sel:profile selector. Valid range 0 - 2 (uint)

# lspci -vvv

f0a2:00:02.0 Ethernet controller: Mellanox Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80)
	Subsystem: Mellanox Technologies Device 0190
	Physical Slot: 1
	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0
	NUMA node: 0
	Region 0: Memory at fc0000000 (64-bit, prefetchable) [size=1M]
	Capabilities: [60] Express (v2) Endpoint, MSI 00
		DevCap:	MaxPayload 512 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
			ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
		DevCtl:	Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
			RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop- FLReset-
			MaxPayload 128 bytes, MaxReadReq 128 bytes
		DevSta:	CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend-
		LnkCap:	Port #0, Speed 8GT/s, Width x8, ASPM L1, Exit Latency L1 <4us
			ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
		LnkCtl:	ASPM Disabled; RCB 64 bytes Disabled- CommClk-
			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
		LnkSta:	Speed unknown, Width x0, TrErr- Train- SlotClk- DLActive- BWMgmt- ABWMgmt-
		DevCap2: Completion Timeout: Range ABC, TimeoutDis+, LTR-, OBFF Not Supported
			 AtomicOpsCap: 32bit- 64bit- 128bitCAS-
		DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
			 AtomicOpsCtl: ReqEn-
		LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
			 EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
	Capabilities: [9c] MSI-X: Enable+ Count=32 Masked-
		Vector table: BAR=0 offset=00002000
		PBA: BAR=0 offset=00003000
	Kernel driver in use: mlx5_core
	Kernel modules: mlx5_core


Fixes to improve kernel stability during the platform event known to trigger this panic were officially released.

The corresponding kernel versions are:

SLES Version

 Kernel Version

SLES 12 SP4 LTSS, released on 2023-05-17


SLES 12 SP5, released on 2023-04-10


SLES 15 SP1 LTSS, released on 2023-04-14


SLES 15 SP2 LTSS, released on 2023-04-10


SLES 15 SP3 LTSS, released on 2023-04-11


SLES 15 SP4, released on 2023-04-18



If there are a large number of bad memory pages which need to be corrected, Hyper-V currently handles the pages one by one, and each correction causes a VF remove event and a VF add event.  When a Linux workload gets a large number of these back-to-back VF add/remove events in a short period of time, it has been found to cause kernel stability issues.  Several race conditions have been found in the pci-hyperv driver which is responsible for these hardware changes.


Top Issue

Additional Information

This issue impacts all Linux distributions.  Microsoft Engineering has pushed fixes to the upstream kernel to handle these platform events more gracefully.
Microsoft has paused the known problematic behavior on the platform and intends to roll out the re-implemented version of the feature at a later time.

More information can be found here:


This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:000021005
  • Creation Date: 22-May-2023
  • Modified Date:22-May-2023
    • SUSE Linux Enterprise Server
    • SUSE Linux Enterprise Server for SAP Applications

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