ESXi Host crashes with a PSOD error, event NFS41_SMEventCreate

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

One or more ESXi hosts may PSOD with stack trace containing the method NFS41_SMEventCreate

PSOD backtrace looks similar to below events:

PanicvPanicInt@vmkernel#nover+0x439 
Panic_vPanic@vmkernel#nover+0x23 
vmk_PanicWithModuleID@vmkernel#nover+0x41 
NFS41_SMEventCreate@(nfs41client)#<None>+0x7d 
NFS41_ConnectionRPCEventCB@(nfs41client)#<None>+0x1b 
[email protected]#1+0x5db 
[email protected]#1+0x35 
CpuSched_StartWorld@vmkernel#nover+0x77 

Environment

VMware vSphere ESXi 7.0.3
VMware vSphere ESXi 6.7
VMware vSphere ESXi 7.0.x

Cause

During NFSv4.1 Server failover, a certain code path fails to release lock when the ESXi receives a different Server Major number from the Server. The host does not PSOD immediately after the server failover, the events keep building in the queue until there is no more free memory available to allocate for the event.

Resolution

The issue is resolved in vSphere 7.0 U3f and later releases

Workaround:

No workaround available. NFS4.1 server failovers may be unplanned, which is outside of user control.