WSLg regression on session 0 (GitHub Actions)

[CarlosNihelton]

Windows Version

10.0.26300.8772

WSL Version

2.9.4.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

6.18.35.2

Distro Version

Ubuntu 26.04

Other Software

No response

Repro Steps

Save the following shell script to C:\Temp:

#!/bin/bash
shopt -s extglob

export WSL_UTF8=1

version=$( wsl.exe --version | head -n1 | cut -d' ' -f3)
version="${version%%*([[:space:]])}"
folder="/mnt/c/Temp/$version"

mkdir "$folder"
wayland-info 2>&1 >"$folder/wl.txt"
cp /mnt/wslg/*.log "$folder"
dmesg | grep -i segfault > "$folder/dmesg.txt"
cat /proc/cmdline > "$folder/cmdline.txt"

(That script runs wayland-info, which is not preinstalled by default. Make sure to have it installed before proceeding. On Ubuntu and Debian that command is available in the apt package wayland-utils)

On an elevated powershell, run psexec to launch wsl.exe on session 0 with your regular interactive user credentials (DOMAIN most likely will be just . for the local computer domain):

psexec -i 0 -u <DOMAIN\USER> -p <PASSWORD> powershell -Command "wsl.exe -u <DISTRO> -- bash /mnt/c/Temp/script.sh.

(psexec comes from Sysinternals, installable via winget).

Expected Behavior

For any recent version of WSL, the outputs of the wayland-info command (C:\Temp\<WSL_VERSION>\wl.txt) should be populated with details about the session, seat and available protocols while the filtered dmesg output (C:\Temp\<WSL_VERSION>\dmesg.txt) should not contain any crash related to WSLg.

Actual Behavior

True for WSL up to 2.7.10. On 2.9.4 the wayland-info output is empty and dmesg.txt shows a crash similar to the following line:

[  107.040670] weston[160]: segfault at 218 ip 000078565b825ffb sp 00007fff1bd92330 error 4 in rdp-backend.so[1cffb,78565b80f000+18000] likely on CPU 2 (core 1, socket 0)

(it looks like an attempt to read an offset from the null pointer - segfault at 0x218, error 4).

Diagnostic Logs

I came across this problem after seeing a Flutter app test crash in CI running on GitHub Actions with no other changes but the WSL version. This particular CI workflow runs the app tests inside WSL. On a faulty run I noticed the following trace coming from the GTK3 layer:

(com.example.sample_app:570): Gdk-CRITICAL **: 07:57:47.797: gdk_seat_get_keyboard: assertion 'GDK_IS_SEAT (seat)' failed

That means we didn't have a seat, pointing to some fundamental issue around the graphical session.

The minimal reproducer I could come up with is running wayland-info. It shows empty on an affected instance.
AFAICT The GitHub actions runner runs as a service (thus session 0) with a user (interactive) account, thus fully capable of running WSL. Hence why using psexec to reproduce the crash: we need the user account but running in session 0. A regular interactive session doesn't experience that crash.

The less scientific but still important part: installing just the four binaries below from WSL 2.7.10 on a system running WSL 2.9.4 fixes the problem, everything else (WSLg image, kernel, distro) left at 2.9.4:

• msrdc.exe
• rdclientax.dll
• rdpnanoTransport.dll
• RdpWinStlHelper.dll

A/B/C result: interactive session → wayland-info populated, no segfault on WSL 2.9.4;
session 0 → wayland-info empty, rdp-backend.so SIGSEGV at ~107 s on 2.9.4;
session 0 → wayland-info populated, no segfault on 2.9.4 with swapped MSRDC binaries.

Inspecting the diff between WSL 2.7.10 and 2.9.3, the most noticeable and untraceable from outside is the upgrade in MSRDC.SessionHost in packages.config ( commit #2a7269e8 / PR #40882 ).

weston.log from a faulty instance:

Date: 2026-07-17 -03
[15:45:15.538] weston 9.0.0
               https://wayland.freedesktop.org
               Bug reports to: https://gitlab.freedesktop.org/wayland/weston/issues/
               Build: 9.0.0-215-ga7e35fda
[15:45:15.538] Command line: /usr/bin/weston --backend=rdp-backend.so --modules=wslgd-notify.so --xwayland --socket=wayland-0 --shell=rdprail-shell.so --log=/mnt/wslg/weston.log --logger-scopes=log,rdp-backend,rdprail-shell
[15:45:15.538] OS: Linux, 6.18.35.2-microsoft-standard-WSL2, #1 SMP PREEMPT_DYNAMIC Wed Jun 17 23:14:00 UTC 2026, x86_64
[15:45:15.538] warning: XDG_RUNTIME_DIR "/mnt/wslg/runtime-dir" is not configured
correctly.  Unix access mode must be 0700 (current mode is 777),
and must be owned by the user (current owner is UID 1000).
Refer to your distribution on how to get it, or
http://www.freedesktop.org/wiki/Specifications/basedir-spec
on how to implement it.
[15:45:15.539] Using config file '/home/wslg/.config/weston.ini'
[15:45:15.540] Output repaint window is 7 ms maximum.
[15:45:15.541] Loading module '/usr/lib/libweston-9/rdp-backend.so'
[15:45:15.548] using FreeRDP version 2.4.0
Date: 2026-07-17 -03
[15:45:15.548] RDP backend: WESTON_RDP_DEBUG_LEVEL: 3
[15:45:15.548] RDP backend: rdp_monitor_refresh_rate: 60000
[15:45:15.548] RDP backend: timer resolution tv_sec:0 tv_nsec:1
[15:45:15.548] RDP backend: Environment dump - start
[15:45:15.548]   WSL2_DEFAULT_APP_ICON=/usr/share/icons/wsl/linux.png
[15:45:15.548]   SHELL=/bin/bash
[15:45:15.548]   WSL2_GUI_APPS_ENABLED=1
[15:45:15.548]   WSL_DISTRO_NAME=
[15:45:15.548]   XCURSOR_PATH=/mnt/wslg/distro/usr/share/icons:/usr/share/icons
[15:45:15.548]   XCURSOR_SIZE=16
[15:45:15.548]   WLOG_APPENDER=file
[15:45:15.548]   NAME=DESKTOP-551PQ9O
[15:45:15.548]   PWD=/home/wslg
[15:45:15.548]   LOGNAME=wslg
[15:45:15.548]   WSL_FEATURE_FLAGS=34
[15:45:15.548]   WSL2_USER_PROFILE=C:\Users\User
[15:45:15.548]   WSL2_DISTRO_NAME=Ubuntu-26.04
[15:45:15.548]   _=/usr/bin/weston
[15:45:15.548]   PULSE_AUDIO_RDP_SINK=/mnt/wslg/PulseAudioRDPSink
[15:45:15.548]   HOME=/home/wslg
[15:45:15.548]   WSLG_SERVICE_ID=00000001-FACB-11E6-BD58-64006A7986D3
[15:45:15.548]   WAYLAND_DISPLAY=wayland-0
[15:45:15.548]   USE_VSOCK=3
[15:45:15.548]   WSL2_DEFAULT_APP_OVERLAY_ICON=/usr/share/icons/wsl/linux.png
[15:45:15.548]   USER=wslg
[15:45:15.548]   DISPLAY=:0
[15:45:15.548]   SHLVL=0
[15:45:15.548]   WSLGD_NOTIFY_SOCKET=/mnt/wslg/weston-notify.sock
[15:45:15.548]   WLOG_FILEAPPENDER_OUTPUT_FILE_PATH=/mnt/wslg
[15:45:15.548]   XDG_RUNTIME_DIR=/mnt/wslg/runtime-dir
[15:45:15.548]   XCURSOR_THEME=whiteglass
[15:45:15.548]   PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
[15:45:15.548]   WESTON_DISABLE_ABSTRACT_FD=1
[15:45:15.548]   WLOG_FILEAPPENDER_OUTPUT_FILE_NAME=wlog.log
[15:45:15.548]   PULSE_AUDIO_RDP_SOURCE=/mnt/wslg/PulseAudioRDPSource
[15:45:15.548]   PULSE_SERVER=unix:/mnt/wslg/PulseServer
[15:45:15.548]   WSL2_INSTALL_PATH=C:\Program Files\WSL
[15:45:15.548]   WESTON_CONFIG_FILE=/home/wslg/.config/weston.ini
[15:45:15.548] RDP backend: Environment dump - end
[15:45:15.548] RDP backend: FreeRDP version: 2.4.0
[15:45:15.548] Using external fd for incoming connections: 3
[15:45:15.548] Default head is being added
[15:45:15.548] Registered plugin API 'weston_rdprail_api_v1' of size 72
[15:45:15.548] RDPAPPLIST_MODULEDIR is set to /usr/lib/rdpapplist
[15:45:15.549] RDP backend: use_rdpapplist = 1
[15:45:15.549] WSL2_SHARED_MEMORY_MOUNT_POINT is not set.
[15:45:15.549] RDP backend: use_gfxredir = 0
[15:45:15.549] RDP backend: enable_hi_dpi_support = 1
[15:45:15.549] RDP backend: enable_fractional_hi_dpi_support = 0
[15:45:15.549] RDP backend: enable_fractional_hi_dpi_roundup = 0
[15:45:15.549] RDP backend: debug_desktop_scaling_factor = 0
[15:45:15.549] RDP backend: enable_window_zorder_sync = 1
[15:45:15.549] RDP backend: enable_window_snap_arrange = 1
[15:45:15.549] RDP backend: enable_window_shadow_remoting = 1
[15:45:15.549] RDP backend: enable_display_power_by_screenupdate = 0
[15:45:15.549] RDP backend: enable_distro_name_title = 1
[15:45:15.549] RDP backend: enable_copy_warning_title = 1
[15:45:15.549] Using VSOCK for incoming connections: 3
[15:45:15.549] Registered plugin API 'weston_rdp_output_api_v1' of size 24
[15:45:15.549] Head attaching: rdp-0, index:0, is_primary: 1
[15:45:15.549] Client desktop upper left coordinate (0,0)
[15:45:15.549] disp_monitor_validate_and_compute_layout:---OUTPUT---
[15:45:15.549] 	rdpMonitor[0]: x:0, y:0, width:0, height:0, is_primary:1
[15:45:15.549] 	rdpMonitor[0]: weston x:0, y:0, width:0, height:0
[15:45:15.549] 	rdpMonitor[0]: physicalWidth:0, physicalHeight:0, orientation:0
[15:45:15.549] 	rdpMonitor[0]: desktopScaleFactor:0, deviceScaleFactor:0
[15:45:15.549] 	rdpMonitor[0]: scale:1, clientScale:1.00
[15:45:15.549] Head mode change:rdp-0 NEW width:0, height:0, scale:1, clientScale:1.000000
[15:45:15.549] move head/output rdp-0 (0,0) -> (0,0)
[15:45:15.549] client origin (0,0) is (0,0) in Weston space
[15:45:15.549] Output 'rdp-0' enabled with head(s) rdp-0
[15:45:15.549] Compositor capabilities:
               arbitrary surface rotation: yes
               screen capture uses y-flip: no
               presentation clock: CLOCK_MONOTONIC_RAW, id 4
               presentation clock resolution: 0.000000001 s
[15:45:15.550] Loading module '/usr/lib/weston/rdprail-shell.so'
[15:45:15.554] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_DEBUG_LEVEL: 3.
Date: 2026-07-17 -03
[15:45:15.554] RDPRAIL-shell: allow-zap:0
[15:45:15.554] RDPRAIL-shell: allow-alt-f4-to-close-app:1
[15:45:15.554] RDPRAIL-shell: binding-modifier:none
[15:45:15.554] RDPRAIL-shell: local-move:0
[15:45:15.554] RDPRAIL-shell: distro name:Ubuntu-26.04 (len:12)
[15:45:15.557] RDPRAIL-shell: WSL2_DEFAULT_APP_ICON:/usr/share/icons/wsl/linux.png (loaded:yes)
[15:45:15.557] RDPRAIL-shell: WSL2_DEFAULT_APP_OVERLAY_ICON:/usr/share/icons/wsl/linux.png (loaded:yes)
[15:45:15.557] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_APPEND_DISTRONAME_STARTMEN:1
[15:45:15.557] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_BLEND_OVERLAY_ICON_APPLIST:1
[15:45:15.557] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_BLEND_OVERLAY_ICON_TASKBAR:1
[15:45:15.557] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_USE_WSLPATH:0
[15:45:15.557] rdp_rail_shell_initialize_notify: shell: distro name: Ubuntu-26.04
[15:45:15.558] app_list_monitor_thread: running in user-distro: Ubuntu-26.04
[15:45:15.559] Loading module '/usr/lib/libweston-9/xwayland.so'
[15:45:15.559] app_list_monitor_thread: inotify_add_watch(/usr/share/applications)
[15:45:15.559] app_list_monitor_thread: monitor /usr/share/applications
[15:45:15.559] app_list_monitor_thread: /usr/local/share/applications doesn't exist, skipping.
[15:45:15.559] app_list_monitor_thread: /var/lib/snapd/desktop/applications doesn't exist, skipping.
[15:45:15.559] app_list_monitor_thread: /var/lib/flatpak/exports/share/applications doesn't exist, skipping.
[15:45:15.559] app list folder[0]: /usr/share/applications
[15:45:15.560] Registered plugin API 'weston_xwayland_v1' of size 32
[15:45:15.560] Registered plugin API 'weston_xwayland_surface_v1' of size 48
[15:45:15.560] Not using abstract fd for Xwayland
[15:45:15.560] xserver listening on display :0
[15:45:15.560] Loading module '/usr/lib/weston/wslgd-notify.so'
[15:45:15.560] desktop file: /usr/share/applications/org.freedesktop.Xwayland.desktop has NoDisplay specified
[15:45:15.560] app list entry failed to update: Key:Xwayland
[15:45:15.560] free_app_entry(): (null): /usr/share/applications/org.freedesktop.Xwayland.desktop
[15:45:15.560] app list folder[1]: /usr/local/share/applications
[15:45:15.560] app list folder[2]: /var/lib/snapd/desktop/applications
[15:45:15.560] app list folder[3]: /var/lib/flatpak/exports/share/applications
[15:45:15.560] ../compositor/wslgd-notify.c: socket connected
[15:45:15.640] Spawned Xwayland server, pid 28
[15:45:15.746] xfixes version: 6.0
[15:45:15.761] created wm, root 912
[15:47:00.294] unable to checkDescriptor for 0x625ac1c6f890
Date: 2026-07-17 -03
[15:47:00.324] weston 9.0.0
               https://wayland.freedesktop.org
               Bug reports to: https://gitlab.freedesktop.org/wayland/weston/issues/
               Build: 9.0.0-215-ga7e35fda
[15:47:00.324] Command line: /usr/bin/weston --backend=rdp-backend.so --modules=wslgd-notify.so --xwayland --socket=wayland-0 --shell=rdprail-shell.so --log=/mnt/wslg/weston.log --logger-scopes=log,rdp-backend,rdprail-shell
[15:47:00.324] OS: Linux, 6.18.35.2-microsoft-standard-WSL2, #1 SMP PREEMPT_DYNAMIC Wed Jun 17 23:14:00 UTC 2026, x86_64
[15:47:00.324] warning: XDG_RUNTIME_DIR "/mnt/wslg/runtime-dir" is not configured
correctly.  Unix access mode must be 0700 (current mode is 777),
and must be owned by the user (current owner is UID 1000).
Refer to your distribution on how to get it, or
http://www.freedesktop.org/wiki/Specifications/basedir-spec
on how to implement it.
[15:47:00.324] Using config file '/home/wslg/.config/weston.ini'
[15:47:00.324] Output repaint window is 7 ms maximum.
[15:47:00.324] Loading module '/usr/lib/libweston-9/rdp-backend.so'
[15:47:00.327] using FreeRDP version 2.4.0
Date: 2026-07-17 -03
[15:47:00.327] RDP backend: WESTON_RDP_DEBUG_LEVEL: 3
[15:47:00.327] RDP backend: rdp_monitor_refresh_rate: 60000
[15:47:00.327] RDP backend: timer resolution tv_sec:0 tv_nsec:1
[15:47:00.327] RDP backend: Environment dump - start
[15:47:00.327]   WSL2_DEFAULT_APP_ICON=/usr/share/icons/wsl/linux.png
[15:47:00.327]   SHELL=/bin/bash
[15:47:00.327]   WSL2_GUI_APPS_ENABLED=1
[15:47:00.327]   WSL_DISTRO_NAME=
[15:47:00.327]   XCURSOR_PATH=/mnt/wslg/distro/usr/share/icons:/usr/share/icons
[15:47:00.327]   XCURSOR_SIZE=16
[15:47:00.327]   WLOG_APPENDER=file
[15:47:00.327]   NAME=DESKTOP-551PQ9O
[15:47:00.327]   PWD=/home/wslg
[15:47:00.327]   LOGNAME=wslg
[15:47:00.327]   WSL_FEATURE_FLAGS=34
[15:47:00.327]   WSL2_USER_PROFILE=C:\Users\User
[15:47:00.327]   WSL2_DISTRO_NAME=Ubuntu-26.04
[15:47:00.327]   _=/usr/bin/weston
[15:47:00.327]   PULSE_AUDIO_RDP_SINK=/mnt/wslg/PulseAudioRDPSink
[15:47:00.327]   HOME=/home/wslg
[15:47:00.327]   WSLG_SERVICE_ID=00000001-FACB-11E6-BD58-64006A7986D3
[15:47:00.327]   WAYLAND_DISPLAY=wayland-0
[15:47:00.327]   USE_VSOCK=3
[15:47:00.327]   WSL2_DEFAULT_APP_OVERLAY_ICON=/usr/share/icons/wsl/linux.png
[15:47:00.327]   USER=wslg
[15:47:00.327]   DISPLAY=:0
[15:47:00.327]   SHLVL=0
[15:47:00.327]   WSLGD_NOTIFY_SOCKET=/mnt/wslg/weston-notify.sock
[15:47:00.327]   WLOG_FILEAPPENDER_OUTPUT_FILE_PATH=/mnt/wslg
[15:47:00.327]   XDG_RUNTIME_DIR=/mnt/wslg/runtime-dir
[15:47:00.327]   XCURSOR_THEME=whiteglass
[15:47:00.327]   PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
[15:47:00.327]   WESTON_DISABLE_ABSTRACT_FD=1
[15:47:00.327]   WLOG_FILEAPPENDER_OUTPUT_FILE_NAME=wlog.log
[15:47:00.327]   PULSE_AUDIO_RDP_SOURCE=/mnt/wslg/PulseAudioRDPSource
[15:47:00.327]   PULSE_SERVER=unix:/mnt/wslg/PulseServer
[15:47:00.327]   WSL2_INSTALL_PATH=C:\Program Files\WSL
[15:47:00.327]   WESTON_CONFIG_FILE=/home/wslg/.config/weston.ini
[15:47:00.327] RDP backend: Environment dump - end
[15:47:00.327] RDP backend: FreeRDP version: 2.4.0
[15:47:00.327] Using external fd for incoming connections: 3
[15:47:00.327] Default head is being added
[15:47:00.327] Registered plugin API 'weston_rdprail_api_v1' of size 72
[15:47:00.327] RDPAPPLIST_MODULEDIR is set to /usr/lib/rdpapplist
[15:47:00.327] RDP backend: use_rdpapplist = 1
[15:47:00.327] WSL2_SHARED_MEMORY_MOUNT_POINT is not set.
[15:47:00.327] RDP backend: use_gfxredir = 0
[15:47:00.327] RDP backend: enable_hi_dpi_support = 1
[15:47:00.327] RDP backend: enable_fractional_hi_dpi_support = 0
[15:47:00.327] RDP backend: enable_fractional_hi_dpi_roundup = 0
[15:47:00.327] RDP backend: debug_desktop_scaling_factor = 0
[15:47:00.327] RDP backend: enable_window_zorder_sync = 1
[15:47:00.327] RDP backend: enable_window_snap_arrange = 1
[15:47:00.327] RDP backend: enable_window_shadow_remoting = 1
[15:47:00.327] RDP backend: enable_display_power_by_screenupdate = 0
[15:47:00.327] RDP backend: enable_distro_name_title = 1
[15:47:00.327] RDP backend: enable_copy_warning_title = 1
[15:47:00.327] Using VSOCK for incoming connections: 3
[15:47:00.327] Registered plugin API 'weston_rdp_output_api_v1' of size 24
[15:47:00.327] Head attaching: rdp-0, index:0, is_primary: 1
[15:47:00.327] Client desktop upper left coordinate (0,0)
[15:47:00.327] disp_monitor_validate_and_compute_layout:---OUTPUT---
[15:47:00.327] 	rdpMonitor[0]: x:0, y:0, width:0, height:0, is_primary:1
[15:47:00.327] 	rdpMonitor[0]: weston x:0, y:0, width:0, height:0
[15:47:00.327] 	rdpMonitor[0]: physicalWidth:0, physicalHeight:0, orientation:0
[15:47:00.327] 	rdpMonitor[0]: desktopScaleFactor:0, deviceScaleFactor:0
[15:47:00.327] 	rdpMonitor[0]: scale:1, clientScale:1.00
[15:47:00.327] Head mode change:rdp-0 NEW width:0, height:0, scale:1, clientScale:1.000000
[15:47:00.327] move head/output rdp-0 (0,0) -> (0,0)
[15:47:00.327] client origin (0,0) is (0,0) in Weston space
[15:47:00.327] Output 'rdp-0' enabled with head(s) rdp-0
[15:47:00.327] Compositor capabilities:
               arbitrary surface rotation: yes
               screen capture uses y-flip: no
               presentation clock: CLOCK_MONOTONIC_RAW, id 4
               presentation clock resolution: 0.000000001 s
[15:47:00.327] Loading module '/usr/lib/weston/rdprail-shell.so'
[15:47:00.333] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_DEBUG_LEVEL: 3.
Date: 2026-07-17 -03
[15:47:00.333] RDPRAIL-shell: allow-zap:0
[15:47:00.333] RDPRAIL-shell: allow-alt-f4-to-close-app:1
[15:47:00.333] RDPRAIL-shell: binding-modifier:none
[15:47:00.333] RDPRAIL-shell: local-move:0
[15:47:00.333] RDPRAIL-shell: distro name:Ubuntu-26.04 (len:12)
[15:47:00.334] RDPRAIL-shell: WSL2_DEFAULT_APP_ICON:/usr/share/icons/wsl/linux.png (loaded:yes)
[15:47:00.334] RDPRAIL-shell: WSL2_DEFAULT_APP_OVERLAY_ICON:/usr/share/icons/wsl/linux.png (loaded:yes)
[15:47:00.334] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_APPEND_DISTRONAME_STARTMEN:1
[15:47:00.334] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_BLEND_OVERLAY_ICON_APPLIST:1
[15:47:00.334] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_BLEND_OVERLAY_ICON_TASKBAR:1
[15:47:00.334] RDPRAIL-shell: WESTON_RDPRAIL_SHELL_USE_WSLPATH:0
[15:47:00.334] rdp_rail_shell_initialize_notify: shell: distro name: Ubuntu-26.04
[15:47:00.335] app_list_monitor_thread: running in user-distro: Ubuntu-26.04
[15:47:00.336] app_list_monitor_thread: inotify_add_watch(/usr/share/applications)
[15:47:00.335] Loading module '/usr/lib/libweston-9/xwayland.so'
[15:47:00.336] app_list_monitor_thread: monitor /usr/share/applications
[15:47:00.336] app_list_monitor_thread: /usr/local/share/applications doesn't exist, skipping.
[15:47:00.336] app_list_monitor_thread: /var/lib/snapd/desktop/applications doesn't exist, skipping.
[15:47:00.336] app_list_monitor_thread: /var/lib/flatpak/exports/share/applications doesn't exist, skipping.
[15:47:00.336] app list folder[0]: /usr/share/applications
[15:47:00.336] desktop file: /usr/share/applications/org.freedesktop.Xwayland.desktop has NoDisplay specified
[15:47:00.336] app list entry failed to update: Key:Xwayland
[15:47:00.336] free_app_entry(): (null): /usr/share/applications/org.freedesktop.Xwayland.desktop
[15:47:00.336] app list folder[1]: /usr/local/share/applications
[15:47:00.336] app list folder[2]: /var/lib/snapd/desktop/applications
[15:47:00.336] app list folder[3]: /var/lib/flatpak/exports/share/applications
[15:47:00.336] Registered plugin API 'weston_xwayland_v1' of size 32
[15:47:00.336] Registered plugin API 'weston_xwayland_surface_v1' of size 48
[15:47:00.336] unlinking stale lock file /tmp/.X0-lock
[15:47:00.336] Not using abstract fd for Xwayland
[15:47:00.336] xserver listening on display :0
[15:47:00.336] Loading module '/usr/lib/weston/wslgd-notify.so'
[15:47:00.337] wet_module_init: connect(/mnt/wslg/weston-notify.sock) failed No such file or directory

Details

---

Why this use case matter?

Running graphical apps inside WSL in GitHub Actions is a good way to smoke test the platform and how well we (the distributions) are integrating with it in an automated fashion.

Secondary observations from logs (not the root cause)

• weston.log: XDG_RUNTIME_DIR "/mnt/wslg/runtime-dir" is not configured correctly. Unix access mode must be 0700 (current mode is 777) — the runtime
  dir is world-writable; also causes dbus to refuse its transient service
  directory. Worth reporting but not the crash trigger.
• dbus: Unknown username "pulse" — the pulse user is absent in the system
  distro; cosmetic.
• wet_module_init: connect(/mnt/wslg/weston-notify.sock) failed appears in the
  post-crash restart (the notify socket from the previous instance is gone).

[github-actions]

Logs are required for review from WSL team

If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'.
Otherwise, please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

How to collect WSL logs

Download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1

The script will output the path of the log file once done.

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Once completed please upload the output files to this GitHub issue.

See Collect WSL logs (recommended method).

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[shuaiyuanxx]

I reproduced this locally and identified the crash root cause.

MSRDC 1.2.7214 does not complete the WSLg DVC/RAIL activation in Windows session 0. After the ~100-second timeout, xf_peer_activate() destroys the peer context, then FreeRDP invokes the registered ContextFree callback and destroys the same context again. The second cleanup dereferences the already-cleared windowId.rdp_backend, causing the observed NULL + 0x218 crash at rdp-backend.so+0x1cffb.

Validation:

• Unpatched WSLg + MSRDC 1.2.7214: reproduced the crash after 106 seconds.
• Patched WSLg + MSRDC 1.2.7214: activation still times out, but Weston no longer crashes.
• Patched WSLg + MSRDC 1.2.6676: activation succeeds and wayland-info reports a valid output and seat.

Therefore, there are two separate issues:

1. A Weston double-cleanup bug triggered by activation failure, this fix should be in weston side.
2. An MSRDC 1.2.7214 session-0 activation regression, which needs an MSRDC-side fix to restore GUI functionality.

[CarlosNihelton]

I think we can remove the needs-author-feedback label, right?

[yanggf8]

Another data point that matches Shawn Yuan (@shuaiyuanxx)'s root cause exactly, with two details that may widen the scope:

1. WSL 2.7.11.0 is also affected. The report says the expected behaviour held "up to 2.7.10" and broke on 2.9.4. We see the identical crash on 2.7.11.0, which narrows the regression window to between 2.7.10 and 2.7.11 rather than something introduced in the 2.9.x line.

2. Session 0 happens without psexec, on a host with an active interactive console. No CI, no service account, no deliberate session-0 launch:

Id     SessionId  ProcessName
22252          0  msrdc          <-- WSLg's RDP client
19356          0  wslservice
 8888          1  explorer       <-- the logged-in interactive session

query session confirms console <user> 1 Active. So a normal desktop machine can end up with msrdc in session 0 — most likely because something in session 0 (here com.docker.service, StartType=Automatic) started the shared WSL VM before the user's session was in play. If that is the mechanism, the "a regular interactive session doesn't experience that crash" note holds only when the VM's first activation came from that interactive session. Worth mentioning because it means users can hit this with no CI involvement and no obvious cause.

Symptoms, consistent with the described double-free in rdp-backend.so:

• /mnt/wslg/stderr.log: in the last 300 lines, 150 weston terminations, every one signal 11, with 149 matching msrdc … exited with status 0 (msrdc leaves cleanly because weston died). No other signal appears.
• Cadence ~104 s, which lines up with the ~100 s activation timeout in the analysis. 2504 crash cycles on a VM up 73 h; still looping.
• Last weston log line before each crash: unable to checkDescriptor for 0x<addr>, after xserver listening on display :0.
• The RDP side is healthy every cycle — wlog.html/wlog.log shows the client accepted and the full channel set negotiated (conctrl, rdpdr, rdpsnd, rail, rail_wi, rail_ri, cliprdr, drdynvc) before the crash.
• Core dumps are captured automatically at %LOCALAPPDATA%\Temp\wsl-crashes\wsl-crash-*-_usr_bin_weston-11.dmp, 107.6 MB each, 10 retained. Happy to attach one.

Environment: WSL 2.7.11.0 (Store) · WSLg 1.0.73.2 · MSRDC 1.2.7214 (same as the analysis) · kernel 6.18.33.2-2 · Windows 10.0.26200.8875 · weston 9.0.0 on Azure Linux 3.0.20260510 (system.vhd dated 2026-05-18) · .wslconfig: networkingMode=mirrored, memory=8GB, swap=4GB, [experimental] hostAddressLoopback=true.

Things that do not help, in case it saves anyone time: killing msrdc.exe (Windows respawns it, the channel renegotiates cleanly, the loop resumes within 1.5 cycles); pkill -9 weston (WSLGd respawns it and it segfaults again — the crash is at startup, so how the previous instance died is irrelevant); wsl --update (reports already up to date, so there is no released build to pick up). Host memory pressure and vsock errors were also checked and ruled out on timeline grounds.

[yanggf8]

Follow-up with the mechanism for the 2.7.x half, since it may matter more than the 2.9.x line: the stable 2.7 branch shipped the same MSRDC, and its changelog does not say so.

packages.config at each tag:

tag	Microsoft.RemoteDesktop.Client.MSRDC.SessionHost
2.7.10	1.2.6676
2.7.11	1.2.7214
2.9.3	1.2.7214
2.9.4	1.2.7214

So the bump that Carlos Nihelton (@CarlosNihelton) bisected to MSRDC.SessionHost was also backported into the stable line at 2.7.11, which is what this machine runs and which crashes identically. The published 2.7.10...2.7.11 changelog lists only "Fix MoveDistribution VHD ownership restore" and "Backport security fixes to release/2.7" — the MSRDC dependency bump is not mentioned, so anyone bisecting from release notes would not find it.

Two practical consequences:

• Users on the stable channel are affected, not only those on 2.9.x pre-releases, and wsl --update offers nothing (2.7.11 is current).
• The verified workaround maps cleanly onto stable: the four binaries from 2.7.10 (MSRDC 1.2.6676) replacing the ones from 2.7.11 (1.2.7214). Same swap, same direction as the A/B/C result above — just from a stable-to-stable pair.

Also confirming Carlos Nihelton (@CarlosNihelton)'s A-case independently on 2.7.11: the crash is session-scoped, not machine-scoped. On this host msrdc.exe and wslservice are in SessionId 0 while explorer is in SessionId 1 with query session reporting console <user> 1 Active — i.e. session 0 arose without psexec and without CI, apparently because a session-0 service (com.docker.service, StartType=Automatic) activated the shared WSL VM before the interactive session did. Might be worth mentioning in any eventual release note, since from the user's side it presents as "WSLg broke by itself".

[yanggf8]

Confirmed fix on stable 2.7.11 — the four-binary swap from 2.7.10 works, and it works with msrdc.exe still in session 0.

Result after replacing the four files in C:\Program Files\WSL with 2.7.10's:

• weston has now been alive 1053 s and counting. Its previous maximum was ~104 s, every cycle, 2500+ times.
• weston.log was recreated and grep -c "unable to checkDescriptor" is 0, still 0 after >1.5 former cycle lengths.
• DISPLAY=:0 xdpyinfo returns normally (it previously alternated between hanging and "unable to open display").

Two things that may help others verify they actually applied it:

1. msrdc.exe's FileVersion does not distinguish 2.7.10 from 2.7.11 — both report 1.2.7214.0. Of the four files, only two differ, and those are the ones to check:

file	2.7.11 (broken)	2.7.10 (working)
msrdc.exe	1.2.7214.0	1.2.7214.0
rdclientax.dll	1.2.7214.0	1.2.7214.0
rdpnanoTransport.dll	3.2605.07003.d8e37d6	3.2509.24001.f05d6d5
RdpWinStlHelper.dll	1.2.7214.0	1.2.6676.0

So RdpWinStlHelper.dll reading 1.2.6676.0 is the reliable "the swap took" check. Checking msrdc.exe alone reports 7214 either way — which briefly convinced me the copy had failed.

2. Copy-Item preserves the source's LastWriteTime, so all four end up dated from the older package (2025-10-22 here). An unchanged-looking timestamp is what success looks like, not failure.

On session 0: msrdc.exe is still in SessionId 0 on this machine and there is no crash. That is consistent with the A/B/C result — session 0 plus the older binaries is fine — and it means session 0 by itself is not sufficient to trigger the bug. Worth stating explicitly since my earlier comment emphasised the session-0 correlation; the operative variable is the MSRDC version, and session 0 only decides whether the broken version's activation path is taken.

One uncontrolled variable, for honesty: com.docker.service was stopped as part of the same procedure (it was the session-0 service suspected of activating the shared WSL VM before login) and is still stopped. So the swap was not perfectly isolated. Given the version evidence above and the reporter's A/B/C, the swap is very likely the operative change, but I did not vary one thing at a time.

Happy to re-test with Docker's service restarted if that data point is useful.