DLM_Free / Heap_Free PSOD in VLANMTUCheck Module
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DLM_Free / Heap_Free PSOD in VLANMTUCheck Module

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Article ID: 318026

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

Symptoms:
  • Host experiences PSOD, below is the snippet of the backtrace is reported:
[0x42003714512f]NMVCFireUnicastTicket@(vlanmtucheck)#<None>+0x48 stack: 0x430481c02f88....
......
[0x420037147827]NMVC_UplinkEventCB@(vlanmtucheck)#<None>+0x47c stack: 0x1004305be6104c0
[0x42003621572d]NetEvent_PostEvent@vmkernel#nover+0x172 ... [0x42003624c12b]Portset_BroadcastEvent@vmkernel#nover ...
cpu103:2098814)0x453ba891be70:[0x420036262b78]UplinkTreeNotify@vmkernel#nover+0x91 stack: 0x4312f0c01d2c

.....
[0x4200362686a6]UplinkDev_UpdateLinkState@vmkernel#nover+0x8f stack: 0xb1d
cpu103:2098814)0x453ba891bf20:[0x420036cd7a7c]ixgben_ReportLinkStatus@(ixgben)#

....
cpu103:2098814)0x453ba891bf40:[0x420036cdb3a2]ixgben_CheckAsyncEvents@(ixgben)#
  • Leading to the PSOD, we see below errors in vmkernel.log:
2021-06-19T01:17:08.557Z cpu68:2097579)VLANMTUCheck: NMVCFireUnicastTicket:819: add ticket failed in state 1:Limit exceeded
2021-06-19T01:17:08.557Z cpu68:2097579)VLANMTUCheck: NMVC_StartPsReq:2551: failed to start uplink request for uplink vmnic5:Limit exceeded
2021-06-19T01:17:08.557Z cpu68:2097579)VLANMTUCheck: NMVCFireUnicastTicket:819: add ticket failed in state 1:Limit exceeded
2021-06-19T01:17:08.557Z cpu68:2097579)VLANMTUCheck: NMVC_StartPsReq:2551: failed to start uplink request for uplink vmnic7:Limit exceeded
2021-06-19T01:17:21.134Z cpu103:2098814)VLANMTUCheck: NMVCAddUplink:1975: Add uplink request for uplink vmnic6:DvsPortset-0
2021-06-19T01:17:21.134Z cpu103:2098814)VLANMTUCheck: NMVCMTULocalChkEventPost:230: local MTU setting MATCHED on uplink vmnic6(DV port 2030).


Environment

VMware vSphere ESXi 7.0.0

Cause

  • It is a heap double free issue related to Health Check component.
  • Issue is generally (considered to be a rare corner case) seen when a new uplink is added to vDS while the Health Check features (vLAN-MTU Health Check / Teaming and Failover Health Check / Beacon Probing) are enabled.

Resolution

+ Scheduled to be fixed in 7.0 U3.

Workaround:
Before adding any new uplink to the vDS, disable the Health Check Features (vLAN-MTU Health Check / Teaming and Failover Health Check / Beacon Probing).