[v2026.922.203725][NvFBC][Linux] Sunshine process regularly hangs when closing applications

No source file or test is identified in the report. Start by reproducing the hang with NvFBC on Linux and inspect the verbose log around CLIENT DISCONNECTED, Waiting for video to end, and Hang detected. Done means stream shutdown completes without leaving Sunshine or the NVIDIA driver stuck and without requiring a physical reboot.

Is there an existing issue for this?

• I have searched the existing issues

Is your issue described in the documentation?

• I have read the documentation

Is your issue present in the latest beta/pre-release?

This issue is present in the latest pre-release

Describe the Bug

Regularly when closing a stream, the sunshine process hangs in the background, with the process apparently stuck in the nvidia driver. Nvidia-smi hangs after this issue begins occurring, and the existing sunshine process cannot be killed. Other GPU tasks continue to work fine after this issue occurs however (running games outside of sunshine for example).

This issue only occurs through sunshine, I have never had an app hang outside of sunshine in this way; I suspect it's related to Nvidia FBC that fails to wrap up completely when a stream is closed.

The app that was being streamed through sunshine is closed successfully.

When this issue occurs, a manual physical restart of the machine is required, since otherwise sudo reboot will simply hang forever as well.

Expected Behavior

Sunshine should never hang.

Additional Context

The collected logs (provided below) are Verbose.

The sunshine process remains as a zombie and can no longer be closed once the issue occurs, requiring a physical reboot of the machine hosting it in order to fix.

Repeatability is odd. Sometimes I have the benefit of being able to close several streams/apps with no issues, sometimes it occurs on the first stream close.

The issue in this instance was reproduced on Moonlight-Web, but I have reproduced this issue in both the dedicated Android Moonlight app and the QT dedicated desktop app.

Host Operating System

Linux

Operating System Version

Ubuntu 24.04.5

Architecture

amd64/x86_64

Package

Linux - deb

GPU Type

NVIDIA

GPU Model

RTX A2000

GPU Driver/Mesa Version

615.71.09

Capture Method

NvFBC (Linux)

Apps

Issue occurs when closing an app/stream. The actual app is irrelevant.

Log output

[2026-09-26 14:02:30.905]: Verbose: Audio [seq 1979, pts 9895] ::  send...
[2026-09-26 14:02:30.905]: Verbose: Audio FEC [1976 0] ::  send...
[2026-09-26 14:02:30.905]: Verbose: Audio FEC [1976 1] ::  send...
[2026-09-26 14:02:30.907]: Info: CLIENT DISCONNECTED
[2026-09-26 14:02:30.910]: Info: Setting default sink to: [auto_null]
[2026-09-26 14:02:30.911]: Error: Couldn't set default-sink [auto_null]: No such entity
[2026-09-26 14:02:30.912]: Debug: PulseAudio context terminated
[2026-09-26 14:02:31.002]: Debug: Waiting for video to end...
[2026-09-26 14:02:33.983]: Debug: /CN=NVIDIA GameStream Client -- verified
[2026-09-26 14:02:33.983]: Debug: TUNNEL :: HTTPS
[2026-09-26 14:02:33.983]: Debug: METHOD :: GET
[2026-09-26 14:02:33.983]: Debug: DESTINATION :: /cancel
[2026-09-26 14:02:33.983]: Debug: Accept-Language -- en-US,*
[2026-09-26 14:02:33.983]: Debug: Accept-Encoding -- zstd, br, gzip, deflate
[2026-09-26 14:02:33.983]: Debug: Connection -- close
[2026-09-26 14:02:33.983]: Debug: User-Agent -- MoonlightWeb/0.1
[2026-09-26 14:02:33.983]: Debug: Host -- 192.168.0.107:47984
[2026-09-26 14:02:33.983]: Debug:  [--] 
[2026-09-26 14:02:33.983]: Debug: uuid -- d743c890-ec14-4fab-8715-96ea7b49a48e
[2026-09-26 14:02:33.983]: Debug: uniqueid -- 49ECBE118DBC1A32
[2026-09-26 14:02:33.983]: Debug:  [--] 
[2026-09-26 14:02:37.375]: Debug: TUNNEL :: NONE
[2026-09-26 14:02:37.375]: Debug: METHOD :: GET
[2026-09-26 14:02:37.375]: Debug: DESTINATION :: /serverinfo
[2026-09-26 14:02:37.375]: Debug: Accept-Language -- en-US,*
[2026-09-26 14:02:37.375]: Debug: Accept-Encoding -- zstd, br, gzip, deflate
[2026-09-26 14:02:37.375]: Debug: Connection -- close
[2026-09-26 14:02:37.375]: Debug: User-Agent -- MoonlightWeb/0.1
[2026-09-26 14:02:37.375]: Debug: Host -- 192.168.0.107:47989
[2026-09-26 14:02:37.375]: Debug:  [--] 
[2026-09-26 14:02:37.375]: Debug: uuid -- 9aa4ef6a-74dc-40ef-a4f1-031e0878d442
[2026-09-26 14:02:37.375]: Debug: uniqueid -- 0123456789ABCDEF
[2026-09-26 14:02:37.375]: Debug:  [--] 
[2026-09-26 14:02:41.002]: Fatal: Hang detected! Session failed to terminate in 10 seconds.

Online logs

No response