ESXi PSOD PF Exception 14 in hbr_filter Module During Delta Sync

Products

• VMware vSphere ESXi

Issue/Introduction

An ESXi host experiences a Purple Screen of Death (PSOD) while the VM is configured with replication.

The PSOD displays a Page Fault error pointing to the hbr_filter module:#PF Exception 14 in world 13561205:LSI-13560595 IP 0x42002da142bd addr 0x18Module(s) involved in panic: [hbr_filter Implements v20.21; built: Jun 8 2025]

The backtrace contains a sequence similar to the following:
[0x42002da142bd]Lwd_Issue@(hbr_filter)#0x165
[0x42002c66388d]VSCSI_IssueCommandBE@vmkernel#nover+0x36
[0x42002c6649a7]VSCSIExecuteCommandInt@vmkernel#nover+0x56c
[0x42002c666680]VSCSI_VmkExecuteCommand@vmkernel#nover+0x99
[0x42002c67b657]LSIProcessReqInt@vmkernel#nover+0x528
[0x42002c67bdf3]LSIProcessRequestRing@vmkernel#nover+0x104

Environment

VMware ESXi 8.0.3
vSphere Replication
VMware Protection and Recovery

Cause

A race condition occurs between the UNMAP path in Lwd_Issue and the Lightweight Delta (LWD) sync process. If the delta sync completes while the lock is temporarily released to create the LwdCreateIoProcessor data structure, the sync completion code changes the state to INACTIVE and sets the pointer to NULL. When Lwd_Issue reacquires the lock, it does not re-verify the state and attempts to read data through the now-NULL pointer (address 0x18), resulting in an invalid memory access and a host crash.

Resolution

There is currently no resolution for this issue. The Broadcom engineering team is actively working on a fix to be included in a future release.

Workaround: To address the current issue and prevent the PSOD user must disable the queuing of UNMAP requests on the affected ESXi hosts.

• Connect to the ESXi host via SSH or ESXi Shell.

• Execute the following command:esxcli system settings advanced set -o /HBR/UnmapDeltaSyncQueueSize -i 0

• Verify the setting has been applied correctly by running:esxcli system settings advanced list -o /HBR/UnmapDeltaSyncQueueSize

• Ensure the "Int Value" field in the output reflects 0.

 

 

Additional Information

Important Note regarding ESXi 8.0.3k (build 25595708): Broadcom recommends upgrading to ESXi 8.0.3k to address and avoid other known HBR/LWD bugs present in earlier 8.0.3 builds. However, this upgrade does not contain the fix for this specific PSOD issue. For now the workaround should be applied on the affected ESXi host.