Fix GPU crash in ScreenProbeCompositeTracesWithScatterCS LumenScreenProbeGather

Development Rendering
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1

Hello Epic Games Support Team,

I would like to share a fix for a Rare GPU Crash in ScreenProbeCompositeTracesWithScatterCS. Crash is often reported as LumenScreenProbeGather crash in Nvidia Aftermath Breadcrumbs.

It was also found in Epic bugs here

https://issues.unrealengine.com/issue/UE-282900

https://issues.unrealengine.com/issue/UE-230838

My PR https://github.com/EpicGames/UnrealEngine/pull/14054

Nvidia Nsight Debug data provided in confidential topic below. File name LumenProbeGatherCS.7z.

[Content removed]

Aftermath info

Device Info:

Status : PageFault

Adapter Reset: False

Engine Reset : True

Marker Data:

[0x0000000000000001, CommandQueue]: [Executing ] LumenScreenProbeGather

Shader Name = Global/FScreenProbeCompositeTracesWithScatterCS/5:/Engine/Private/Lumen/LumenScreenProbeFiltering.usf|ScreenProbeCompositeTracesWithScatterCS

You can ask me for additional information if you need.

Best regards

2

Steps to Reproduce

You can ask me for additional information if you need.

3

Hi Oleksii,

Thanks for submitting a fix for this crash. How did you end up reproducing the issue? One reason we have not had much movement on our end regarding this bug is that we cannot reliably reproduce the crash. In any case, I have informed the team of your change, and they will review it as soon as possible and get back to you with any feedback they might have.

4

Hi [mention removed]​

Thank you for a quick response. I don’t have exact repro. The issue was found in our crash reporting system and I was lucky enough it happens during automation game-play testing, which has Aftermath dumps always enabled. Looking forward for UE P4 CL or git commit to properly cherry pick it into our engine.

Cvars below were enabled during that specific run when we collected Aftermath data with nvdbg file, but I think the issue repeats without them too. We just were not lucky enough to collect nvdbg file that would tell us that in our earlier runs.

r.RDG.ParallelExecute=0

r.RDG.Debug.FlushGPU=1

Best regards

5

Ok, thanks for letting me know! This is still valuable information to share with the team, so I appreciate the effort you have made. I can’t give you an exact time on when the PR will be reviewed, and with the holidays and other deadlines coming up, the review might get pushed back into early next year (think end of January). If you haven’t heard anything from us by then, please give this ticket another ping, and I will try to move things along.

6

@TimStullich
@anonymous-edc
Thanks so much for this!

We have a consistent reproduction of this crash on a specific hardware spec:

Interesting Breadcrumb bits:

<Name>AsyncCompute Queue 0</Name>
<FullHash>BC8605957F8E20CF02E5BF4C74EEC45C6ED65F35</FullHash>
<ActiveHash>2F6DE0AE5367F565A0391D43C0034FF7A7509716</ActiveHash>
<Breadcrumbs>
{
    {
        Frame 7070
    }
    ,A,
    {
        {
            {
                LumenSceneLighting%s
            }
            ,A
        }
        ,
        {
            {
                LumenScreenProbeGather
            }
            ,A
        }
        ,
        {
            {
                PostProcessing
            }
            ,N,
            {
                {
                    {
                        TemporalSuperResolution(sg.AntiAliasingQuality=%d%s) %dx%d -&gt; %dx%d
                    }
                    ,N
                }
            }
        }
    }
}

Here are the hardware details:

Name NVIDIA GeForce RTX 4080 Laptop GPU
PNP Device ID PCI\VEN_10DE&DEV_27A0&SUBSYS_13CE1462&REV_A1\4&110685B3&0&0008
Adapter Type NVIDIA GeForce RTX 4080 Laptop GPU, NVIDIA compatible
Adapter Description NVIDIA GeForce RTX 4080 Laptop GPU
Adapter RAM (1,048,576) bytes
Installed Drivers C:\WINDOWS\System32\DriverStore\FileRepository\nvmii.inf_amd64_8cd7780d7719b1eb\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvmii.inf_amd64_8cd7780d7719b1eb\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvmii.inf_amd64_8cd7780d7719b1eb\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvmii.inf_amd64_8cd7780d7719b1eb\nvldumdx.dll
Driver Version 32.0.15.9186
INF File oem402.inf (Section152 section)
Color Planes Not Available
Color Table Entries 4294967296
Resolution 3840 x 2160 x 60 hertz
Bits/Pixel 32
Memory Address 0x000000005E000000-0x000000005EFFFFFF
Memory Address 0x0000006400000000-0x0000006401FFFFFF
IRQ Channel IRQ 4294967247
Driver C:\WINDOWS\SYSTEM32\DRIVERSTORE\FILEREPOSITORY\NVMII.INF_AMD64_8CD7780D7719B1EB\NVLDDMKM.SYS (32.0.15.9186, 100.45 MB (105,330,920 bytes), 2/2/2026 10:38 AM)
OS Name Microsoft Windows 11 Pro
Version 10.0.26100 Build 26100
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name ------------
System Manufacturer Micro-Star International Co., Ltd.
System Model Vector GP68HX 12VH
System Type x64-based PC
System SKU 15M1.5
Processor 12th Gen Intel(R) Core™ i9-12900HX, 2300 Mhz, 16 Core(s), 24 Logical Processor(s)
BIOS Version/Date American Megatrends International, LLC. E15M1IMS.50F, 10/31/2023
SMBIOS Version 3.5
Embedded Controller Version 255.255
BIOS Mode UEFI
BaseBoard Manufacturer Micro-Star International Co., Ltd.
BaseBoard Product MS-15M1
BaseBoard Version REV:1.0
Platform Role Mobile
Secure Boot State On
PCR7 Configuration Elevation Required to View
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = 10.0.26100.1
User Name ---------------
Time Zone Pacific Standard Time
Installed Physical Memory (RAM) 32.0 GB
Total Physical Memory 31.7 GB
Available Physical Memory 17.6 GB
Total Virtual Memory 63.7 GB
Available Virtual Memory 43.6 GB
Page File Space 32.0 GB