Missing atomic increment during DvFilters creation could lead to PSOD on ESXI

Products

• VMware vDefend Firewall

Issue/Introduction

・The ESXi host crashes with a PSOD
・The PSOD backtrace may contain the following lines

[vmkernel-zdump.1.FRAG-00001
     -------------
     2024-09-29T17:02:47.123Z cpu10:2098165)@BlueScreen: #PF Exception 14 in world XXXXXX :dvfilter IP 0x42002090XXXX addr 0x28
     PTEs:0x803851a023;0x803851b023;0x907d300023;0x0;
     2024-09-29T17:02:47.124Z cpu10:2098165)Code start: 0x420020800000 VMK uptime: 822:11:58:49.688
     2024-09-29T17:02:47.124Z cpu10:2098165)0x45395381b558:[0x420020905024]MCS_DoAcqWriteLockWithRA@vmkernel#nover+0x30 stack: 0x4200222cdee9
     2024-09-29T17:02:47.125Z cpu10:2098165)0x45395381b560:[0x42002082baf5]vmk_SpinlockWriteLock@vmkernel#nover+0x16 stack: 0x420045800000
     2024-09-29T17:02:47.126Z cpu10:2098165)0x45395381b570:[0x4200222cdee8]pfioctl@(nsxt-vsip-17884003)#<None>+0x2d stack: 0x45395fa1f140
     2024-09-29T17:02:47.127Z cpu10:2098165)0x45395381b8e0:[0x4200222dd073]PFDelAllAlgs@(nsxt-vsip-17884003)#<None>+0x50 stack: 0xffffffff
     2024-09-29T17:02:47.127Z cpu10:2098165)0x45395381bea0:[0x4200222dd370]PFUnregisterFilter@(nsxt-vsip-17884003)#<None>+0x9 stack: 0x43134f66ac40

Environment

VMware NSX-T Data Center 
VMware NSX-T Data Center 3.1.X

Cause

This issue is caused by a missing atomic increment during DvFilters creation, which could lead to PSOD during DvFilters deletion. 

Resolution

The fix is available starting in NSX-T 3.2.1

Additional Information

Impact/Risk: This is a corner case and does not always occur at the time of the DvFilter deletion process.