[BUG] titlebar is too small for hi-dpi

[ICHx]

Update:
Adding the wayland env solved for titlebar scaling issue. But with wayland there is window resize issue for hidpi screen.

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Firefox is scaled up but titlebar is not
Cursor is also not scaled up, but remedied with css-cursor option enabled

Expected Behavior

Firefox is scaled up along with titlebar

Steps To Reproduce

1. open localhost:3000/ on hi-dpi display
2. session is automatically set to 200% UI scaling
3. browser is scaled up automatically

Environment

- OS: macOS Tahoe 26.3.1
- How docker service was installed: k3s 1.35 on remote cluster

CPU architecture

x86-64

Docker creation

apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "4"
  labels:
    app: firefox
  name: firefox
  namespace: default
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: firefox
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: firefox
    spec:
      containers:
      - image: lscr.io/linuxserver/firefox:latest
        imagePullPolicy: Always
        name: firefox
        ports:
        - containerPort: 3000
          protocol: TCP
        - containerPort: 3001
          protocol: TCP
        resources:
          limits:
            cpu: 500m
            memory: 3G
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      terminationGracePeriodSeconds: 30

Container logs

firefox-686dc975d8-74x95 INFO:selkies_gamepad:Gamepad /tmp/selkies_js0.sock: Event processor started.
firefox-686dc975d8-74x95 INFO:selkies_gamepad:JS interposer server listening on /tmp/selkies_js0.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:Gamepad /tmp/selkies_js1.sock: Event processor started.
firefox-686dc975d8-74x95 INFO:selkies_gamepad:JS interposer server listening on /tmp/selkies_js1.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:Gamepad /tmp/selkies_js2.sock: Event processor started.
firefox-686dc975d8-74x95 INFO:selkies_gamepad:JS interposer server listening on /tmp/selkies_js2.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:Gamepad /tmp/selkies_js3.sock: Event processor started.
firefox-686dc975d8-74x95 INFO:selkies_gamepad:JS interposer server listening on /tmp/selkies_js3.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:EVDEV interposer server listening on /tmp/selkies_event1000.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:EVDEV interposer server listening on /tmp/selkies_event1001.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:EVDEV interposer server listening on /tmp/selkies_event1002.sock
firefox-686dc975d8-74x95 INFO:selkies_gamepad:EVDEV interposer server listening on /tmp/selkies_event1003.sock
firefox-686dc975d8-74x95 dbus-daemon[284[]: [system[] Activating service name='org.freedesktop.login1' requested by ':1.10' (uid=911 pid=397 comm="/usr/lib/firefox/firefox") (using servicehelper)
firefox-686dc975d8-74x95 dbus-daemon[284[]: [system[] Activating service name='org.freedesktop.timedate1' requested by ':1.10' (uid=911 pid=397 comm="/usr/lib/firefox/firefox") (using servicehelper)
firefox-686dc975d8-74x95 dbus-daemon[284[]: [system[] Activated service 'org.freedesktop.login1' failed: Failed to execute program org.freedesktop.login1: Permission denied
firefox-686dc975d8-74x95 dbus-daemon[462[]: Failed to write data to pipe!
firefox-686dc975d8-74x95 INFO:data_websocket:Legacy client ('127.0.0.1', 47644) connected. Role: controller, Slot: None
firefox-686dc975d8-74x95 INFO:data_websocket:Data WebSocket connected from ('127.0.0.1', 47644)
firefox-686dc975d8-74x95 INFO:data_websocket:Sending last known cursor to new client ('127.0.0.1', 47644)
firefox-686dc975d8-74x95 INFO:data_websocket:Attempting to establish PulseAudio connection...
firefox-686dc975d8-74x95 INFO:data_websocket:PulseAudio connection established.
firefox-686dc975d8-74x95 INFO:data_websocket:Registering new client for display: primary
firefox-686dc975d8-74x95 INFO:data_websocket:Applying and sanitizing client settings for 'primary' (initial=True)
firefox-686dc975d8-74x95 INFO:data_websocket:DPI changed from None to 192. Applying system-level change.
firefox-686dc975d8-74x95 INFO:gst_app_resize:Openbox detected. Applying xrdb for DPI 192.
firefox-686dc975d8-74x95 INFO:gst_app_resize:Wrote 'Xft.dpi:   192' to /config/.Xresources.
firefox-686dc975d8-74x95 INFO:gst_app_resize:Successfully loaded /config/.Xresources using xrdb.
firefox-686dc975d8-74x95 INFO:gst_app_resize:Wrote font and DPI settings to /config/.xsettingsd.
firefox-686dc975d8-74x95 INFO:gst_app_resize:Found xsettingsd process with PID: 300.
firefox-686dc975d8-74x95 xsettingsd: Reloading configuration
firefox-686dc975d8-74x95 xsettingsd: Loaded 5 settings from /config/.xsettingsd
firefox-686dc975d8-74x95 INFO:gst_app_resize:Sent SIGHUP to xsettingsd process 300 to reload config.
firefox-686dc975d8-74x95 INFO:data_websocket:Initial setup or dimensional change detected for 'primary'. Performing full display reconfiguration.
firefox-686dc975d8-74x95 INFO:data_websocket:Starting display reconfiguration...
firefox-686dc975d8-74x95 INFO:data_websocket:Calculating new extended desktop layout from ALL clients...
firefox-686dc975d8-74x95 INFO:data_websocket:Layout calculated: Total Size=2752x1762. Layouts: {'primary': {'x': 0, 'y': 0, 'w': 2752, 'h': 1762}}
firefox-686dc975d8-74x95 INFO:data_websocket:Mode 2752x1762 not found. Creating it.
firefox-686dc975d8-74x95 INFO:data_websocket:Defining logical monitors for the window manager...
firefox-686dc975d8-74x95 INFO:data_websocket:Starting separate capture instances for each ACTIVE display region...
firefox-686dc975d8-74x95 INFO:data_websocket:Client 'primary' is active. Starting its capture.
firefox-686dc975d8-74x95 INFO:data_websocket:Preparing to start capture for display='primary': Res=2752x1762, Offset=0x0
firefox-686dc975d8-74x95 INFO:data_websocket:Video chunk sender started for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:SUCCESS: Capture started for 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:New frame backpressure task started for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:Broadcasting primary stream resolution to all clients: {"type": "stream_resolution", "width": 2752, "height": 1762}
firefox-686dc975d8-74x95 INFO:data_websocket:Broadcasting display config update: DISPLAY_CONFIG_UPDATE,{"type": "display_config_update", "displays": ["primary"[]}
firefox-686dc975d8-74x95 INFO:data_websocket:Display reconfiguration finished successfully.
firefox-686dc975d8-74x95 INFO:data_websocket:Reconfiguration process complete (state unlocked).
firefox-686dc975d8-74x95 INFO:data_websocket:Initial client settings message processed by ws_handler.
firefox-686dc975d8-74x95 INFO:data_websocket:Initial setup: Primary client connected, audio not active, attempting start.
firefox-686dc975d8-74x95 INFO:data_websocket:Starting pcmflux audio pipeline...
firefox-686dc975d8-74x95 INFO:data_websocket:pcmflux settings: device='output.monitor', bitrate=320000, channels=2
firefox-686dc975d8-74x95 INFO:data_websocket:Frame-based backpressure logic task started for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:Client settings received, proceeding with backpressure loop for 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:pcmflux audio capture started successfully.
firefox-686dc975d8-74x95 [pcmflux[] Attempting to connect to PulseAudio device: output.monitor...
firefox-686dc975d8-74x95 INFO:data_websocket:pcmflux audio chunk broadcasting task started.
firefox-686dc975d8-74x95 X Shared Memory Extension available.
firefox-686dc975d8-74x95 XShm setup complete for 2752x1762.
firefox-686dc975d8-74x95 CPU cores available: 2
firefox-686dc975d8-74x95 Stream settings active -> Res: 2752x1762 | FPS: 60.0 | Stripes: 1 | Mode: H264 (CPU) FullFrame | CRF: 25 | PaintOver CRF: 18 (Burst: 5f) | Colorspace: I420 (Limited Range) | Damage Thresh: 10f | Damage Dur: 20f
firefox-686dc975d8-74x95 [pcmflux[] SUCCESS: Connected to PulseAudio.
firefox-686dc975d8-74x95 [pcmflux[] SUCCESS: Opus encoder created.
firefox-686dc975d8-74x95 [pcmflux[] Capture loop started. Device: output.monitor, Rate: 48000, Channels: 2, Bitrate: 320 kbps, VBR: On, Silence Gate: Off, Debug Logging: Off, PCM Chunk: 3840 bytes
firefox-686dc975d8-74x95 INFO:data_websocket:Received resize request for primary: 2752x1760 from ('127.0.0.1', 47644)
firefox-686dc975d8-74x95 INFO:gst_app_resize:on_resize_handler for display 'primary' with resolution: 2752x1760
firefox-686dc975d8-74x95 INFO:gst_app_resize:Display client 'primary' dimensions updated to 2752x1760. Triggering reconfiguration.
firefox-686dc975d8-74x95 INFO:data_websocket:Starting display reconfiguration...
firefox-686dc975d8-74x95 INFO:data_websocket:Stopping all existing capture and backpressure tasks...
firefox-686dc975d8-74x95 INFO:data_websocket:Backpressure logic task for 'primary' cancelled.
firefox-686dc975d8-74x95 INFO:data_websocket:Backpressure logic task for 'primary' finished.
firefox-686dc975d8-74x95 INFO:data_websocket:Backpressure task for 'primary' was stopped. Resetting its frame IDs.
firefox-686dc975d8-74x95 INFO:data_websocket:Resetting frame IDs for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:Broadcasting primary pipeline reset to all 1 clients: PIPELINE_RESETTING primary
firefox-686dc975d8-74x95 Capture loop stopped. X resources released.
firefox-686dc975d8-74x95 INFO:data_websocket:All capture instances, senders, and backpressure tasks stopped.
firefox-686dc975d8-74x95 INFO:data_websocket:Calculating new extended desktop layout from ALL clients...
firefox-686dc975d8-74x95 INFO:data_websocket:Layout calculated: Total Size=2752x1760. Layouts: {'primary': {'x': 0, 'y': 0, 'w': 2752, 'h': 1760}}
firefox-686dc975d8-74x95 INFO:data_websocket:Video chunk sender for 'primary' cancelled.
firefox-686dc975d8-74x95 INFO:data_websocket:Video chunk sender for 'primary' finished.
firefox-686dc975d8-74x95 INFO:data_websocket:Mode 2752x1760 not found. Creating it.
firefox-686dc975d8-74x95 INFO:data_websocket:Defining logical monitors for the window manager...
firefox-686dc975d8-74x95 INFO:data_websocket:Starting separate capture instances for each ACTIVE display region...
firefox-686dc975d8-74x95 INFO:data_websocket:Client 'primary' is active. Starting its capture.
firefox-686dc975d8-74x95 INFO:data_websocket:Preparing to start capture for display='primary': Res=2752x1760, Offset=0x0
firefox-686dc975d8-74x95 INFO:data_websocket:Video chunk sender started for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:SUCCESS: Capture started for 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:New frame backpressure task started for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:Broadcasting primary stream resolution to all clients: {"type": "stream_resolution", "width": 2752, "height": 1760}
firefox-686dc975d8-74x95 INFO:data_websocket:Broadcasting display config update: DISPLAY_CONFIG_UPDATE,{"type": "display_config_update", "displays": ["primary"[]}
firefox-686dc975d8-74x95 INFO:data_websocket:Display reconfiguration finished successfully.
firefox-686dc975d8-74x95 INFO:data_websocket:Reconfiguration process complete (state unlocked).
firefox-686dc975d8-74x95 X Shared Memory Extension available.
firefox-686dc975d8-74x95 XShm setup complete for 2752x1760.
firefox-686dc975d8-74x95 CPU cores available: 2
firefox-686dc975d8-74x95 Stream settings active -> Res: 2752x1760 | FPS: 60.0 | Stripes: 1 | Mode: H264 (CPU) FullFrame | CRF: 25 | PaintOver CRF: 18 (Burst: 5f) | Colorspace: I420 (Limited Range) | Damage Thresh: 10f | Damage Dur: 20f
firefox-686dc975d8-74x95 INFO:data_websocket:Frame-based backpressure logic task started for display 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:Client settings received, proceeding with backpressure loop for 'primary'.
firefox-686dc975d8-74x95 INFO:data_websocket:Received START_AUDIO command from client for server-to-client audio.
firefox-686dc975d8-74x95 INFO:data_websocket:START_AUDIO: pcmflux audio pipeline already active.
firefox-686dc975d8-74x95 [pcmflux[] First non-silent audio chunk detected! Encoding...

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[thelamer]

use PIXELFLUX_WAYLAND=true env var, this will be default soon. X11 lacks the right scaling primatives basically you need to restart openbox to get it to take and that is not realistic in this situation.

[ICHx]

thanks, let me try

[ICHx]

Thanks, this worked (CSD titlebar is used instead).

now the problem with wayland is when the outer browser window is resized, the screen go black and then lost hi-dpi settings.
Changing UI Scaling to and forth 200% fixed this temporarily, toggling hi-dpi can't fix, a tab refresh also fixed the issue.

Before resize window

After resize window

[thelamer]

I cannot replicate this please use a clean browsing session. Also this is not a support forum this is for filing bugs, if you truly believe something is broken prove it.

2026-03-24.16-27-10.mp4

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[ICHx]

This is reproducible in a clean environment. A core-dump was observed in the log everytime a resize happened.

firefox-795b5f584f-h82ch INFO:webrtc_input:Clipboard changed. Sending content (text/plain)
firefox-795b5f584f-h82ch INFO:data_websocket:Received resize request for primary: 3464x2076 from ('127.0.0.1', 50196)
firefox-795b5f584f-h82ch INFO:gst_app_resize:on_resize_handler for display 'primary' with resolution: 3464x2076
firefox-795b5f584f-h82ch INFO:gst_app_resize:Wayland Resize: Updating primary to 3464x2076 and restarting pipeline.
firefox-795b5f584f-h82ch INFO:data_websocket:Stopping all streams for display 'primary'...
firefox-795b5f584f-h82ch [Wayland] Capture loop stopped.
firefox-795b5f584f-h82ch INFO:data_websocket:Successfully stopped all streams for display 'primary'.
firefox-795b5f584f-h82ch INFO:data_websocket:Preparing to start capture for display='primary': Res=3464x2076, Offset=0x0
firefox-795b5f584f-h82ch INFO:data_websocket:Registered Wayland cursor callback for 'primary'
firefox-795b5f584f-h82ch INFO:data_websocket:Video chunk sender for 'primary' cancelled.
firefox-795b5f584f-h82ch INFO:data_websocket:Video chunk sender for 'primary' finished.
firefox-795b5f584f-h82ch INFO:data_websocket:Video chunk sender started for display 'primary'.
firefox-795b5f584f-h82ch [Wayland] Configuring Output: 3464x2076 @ 60.00 FPS (Scale 1.00)
firefox-795b5f584f-h82ch INFO:data_websocket:SUCCESS: Capture started for 'primary'.
firefox-795b5f584f-h82ch [Wayland] CPU encoding selected (use_cpu=true or vaapi_node=-1).
firefox-795b5f584f-h82ch [Wayland] Decision: No GPU Encoder available -> Using CPU Software Encoding.
firefox-795b5f584f-h82ch Stream settings active -> Res: 3464x2076 | FPS: 60.0 | Stripes: 1 | Mode: H264 (CPU) FullFrame | CRF: 25 | PaintOver CRF: 18 (Burs
firefox-795b5f584f-h82ch /defaults/startwm_wayland.sh: line 10:   596 Bus error               (core dumped) labwc > /dev/null 2>&1
firefox-795b5f584f-h82ch No desktop processes found to terminate.
firefox-795b5f584f-h82ch [svc-de] Wayland mode: Waiting for socket at /config/.XDG/wayland-1...
firefox-795b5f584f-h82ch [svc-de] /config/.XDG/wayland-1 found launching de
firefox-795b5f584f-h82ch dbus-daemon[309]: [system] Activating service name='org.freedesktop.login1' requested by ':1.21' (uid=911 pid=1652 comm="/usr/lib/
firefox-795b5f584f-h82ch dbus-daemon[309]: [system] Activating service name='org.freedesktop.timedate1' requested by ':1.21' (uid=911 pid=1652 comm="/usr/l
firefox-795b5f584f-h82ch dbus-daemon[309]: [system] Activated service 'org.freedesktop.login1' failed: Failed to execute program org.freedesktop.login1: Pe

Host OS info

linux: 4.18.0-553.109.1.el8_10.x86_64 #1 SMP Tue Mar 3 16:05:15 UTC 2026 x86_64 x86_64 x86_64 GNU/Linux

cat /etc/os-release
NAME="Rocky Linux"
VERSION="8.10 (Green Obsidian)"
ID="rocky"
ID_LIKE="rhel centos fedora"
VERSION_ID="8.10"
PLATFORM_ID="platform:el8"
PRETTY_NAME="Rocky Linux 8.10 (Green Obsidian)"
ANSI_COLOR="0;32"
LOGO="fedora-logo-icon"
CPE_NAME="cpe:/o:rocky:rocky:8:GA"
HOME_URL="https://rockylinux.org/"
BUG_REPORT_URL="https://bugs.rockylinux.org/"
SUPPORT_END="2029-05-31"
ROCKY_SUPPORT_PRODUCT="Rocky-Linux-8"
ROCKY_SUPPORT_PRODUCT_VERSION="8.10"
REDHAT_SUPPORT_PRODUCT="Rocky Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="8.10"

[thelamer]

Kernel 4.18 would be my guess or not using docker-ce that is what we test, upgrade your server or deal with tiny X11 bars.

I don't test on decade old kernels and this is bleeding edge stuff. I can tell you though I will not be putting effort into the X11 side in the future and am in the process of transitioning images.

Edit: just in general I am distracted right now, I should just keep working and hop into this when I have time, but my brain does not work like that. Apologies if any of this comes off as combative.

[ICHx]

Thanks, I may test with newer kernels

[thelamer]

I was able to replicate this in software mode, you need to go at heavy res (4k plus) the specific thing is labwc crashing when scaled.

Backtrace

0x00007fcf7ed85ee3 in ?? () from /lib/x86_64-linux-gnu/libpixman-1.so.0
#0  0x00007fcf7ed85ee3 in ?? () from /lib/x86_64-linux-gnu/libpixman-1.so.0
#1  0x00007fcf7ed86156 in ?? () from /lib/x86_64-linux-gnu/libpixman-1.so.0
#2  0x00007fcf7ed01522 in pixman_image_composite32 () from /lib/x86_64-linux-gnu/libpixman-1.so.0
#3  0x00007fcf7f4127ce in ?? () from /lib/x86_64-linux-gnu/libwlroots-0.18.so
#4  0x00007fcf7f43a9f2 in wlr_scene_output_build_state () from /lib/x86_64-linux-gnu/libwlroots-0.18.so
#5  0x000055d727ef900e in ?? ()
#6  0x000055d727edcd64 in ?? ()
#7  0x00007fcf7f4f7b4c in wl_signal_emit_mutable () from /lib/x86_64-linux-gnu/libwayland-server.so.0
#8  0x00007fcf7f4f9b23 in wl_event_loop_dispatch_idle () from /lib/x86_64-linux-gnu/libwayland-server.so.0
#9  0x00007fcf7f4f9d52 in wl_event_loop_dispatch () from /lib/x86_64-linux-gnu/libwayland-server.so.0
#10 0x00007fcf7f4f7525 in wl_display_run () from /lib/x86_64-linux-gnu/libwayland-server.so.0
#11 0x000055d727ed2b69 in ?? ()
#12 0x00007fcf7e3f4ca8 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#13 0x00007fcf7e3f4d65 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
#14 0x000055d727ed2cb1 in ?? ()

This only happens when the desktop is scaled and you are using the pixman software renderer it does not occur when a GPU is used.

Need some time for an actual root cause but I suspect 32 bit libs in pixman.

[thelamer]

Ok I have the exact issue, wlroots is supposed to have safety rails for this but at high resolutions there is a race with downsizing the texture, it truncates the memory region and labwc tried to push a frame to it at the old resolution, specific issue:

Thread 1 "labwc" received signal SIGBUS, Bus error.
0x00007f38a5f93ee7 in ?? () from /lib/x86_64-linux-gnu/libpixman-1.so.0
(gdb) bt
#0  0x00007f38a5f93ee7 in ??? () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#1  0x00007f38a5f94156 in ??? () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#2  0x00007f38a5f0f522 in pixman_image_composite32 () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#3  0x0000561203c36a56 in render_pass_add_texture (wlr_pass=0x561234561870, options=0x7ffe4cb8b3d0) at ../subprojects/wlroots/render/pixman/pass.c:185
#4  0x0000561203b908d3 in wlr_render_pass_add_texture (render_pass=0x561234561870, options=0x7ffe4cb8b3d0) at ../subprojects/wlroots/render/pass.c:28
#5  0x0000561203bcc0dd in scene_entry_render (entry=0x561234a63050, data=0x7ffe4cb8b6a0) at ../subprojects/wlroots/types/scene/wlr_scene.c:1438
#6  0x0000561203bce413 in wlr_scene_output_build_state (scene_output=0x5612344c2db0, state=0x561234508a18, options=0x7ffe4cb8b700) at ../subprojects/wlroots/types/scene/wlr_scene.c:2294
#7  0x0000561203b6717b in lab_wlr_scene_output_commit (scene_output=0x5612344c2db0, state=0x561234508a18) at ../src/common/scene-helpers.c:118
#8  0x0000561203b44ea4 in handle_output_frame (listener=0x561234508b68, data=0x561234483520) at ../src/output.c:148
#9  0x00007f38a601db4c in wl_signal_emit_mutable () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#10 0x0000561203bc4384 in wlr_output_send_frame (output=0x561234483520) at ../subprojects/wlroots/types/output/output.c:804
#11 0x0000561203bc43c8 in schedule_frame_handle_idle_timer (data=0x561234483520) at ../subprojects/wlroots/types/output/output.c:812
#12 0x00007f38a601fb23 in wl_event_loop_dispatch_idle () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#13 0x00007f38a601fd52 in wl_event_loop_dispatch () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#14 0x00007f38a601d525 in wl_display_run () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#15 0x0000561203b4480e in main (argc=1, argv=0x7ffe4cb8c658) at ../src/main.c:273
(gdb) frame 3
#3  0x0000561203c36a56 in render_pass_add_texture (wlr_pass=0x561234561870, options=0x7ffe4cb8b3d0) at ../subprojects/wlroots/render/pixman/pass.c:185
185			pixman_image_composite32(op, texture->image, mask, buffer->image,
(gdb) info locals
pass = 0x561234561870
texture = 0x5612345658c0
buffer = 0x561234564730
op = PIXMAN_OP_SRC
src_fbox = {x = 0, y = 0, width = 3840, height = 2018}
src_box = {x = 0, y = 0, width = 3840, height = 2018}
dst_box = {x = 0, y = 26, width = 3840, height = 2018}
mask = 0x0
alpha = 1
src_box_transformed = {x = 0, y = 0, width = 3840, height = 2018}
(gdb) print *options
$1 = {texture = 0x5612345658c0, src_box = {x = 0, y = 0, width = 3840, height = 2018}, dst_box = {x = 0, y = 26, width = 3840, height = 2018}, alpha = 0x561234a58be8, clip = 0x7ffe4cb8b480, transform = WL_OUTPUT_TRANSFORM_NORMAL, filter_mode = WLR_SCALE_FILTER_BILINEAR, 
  blend_mode = WLR_RENDER_BLEND_MODE_NONE, wait_timeline = 0x0, wait_point = 0}

[thelamer]

Bypassing it looks specifically like it is the fill function:

Thread 1 "labwc" received signal SIGBUS, Bus error.
0x00007fad884f05c7 in ?? () from /lib/x86_64-linux-gnu/libpixman-1.so.0
(gdb) bt
#0  0x00007fad884f05c7 in ??? () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#1  0x00007fad884d295c in ??? () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#2  0x00007fad8848c67d in pixman_fill () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#3  0x00007fad884ccf2f in ??? () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#4  0x00007fad8848c522 in pixman_image_composite32 () at /lib/x86_64-linux-gnu/libpixman-1.so.0
#5  0x000055a2228b4c6d in render_pass_add_rect (wlr_pass=0x55a230803f00, options=0x7ffdbca99830) at ../subprojects/wlroots/render/pixman/pass.c:221
#6  0x000055a22280e99e in wlr_render_pass_add_rect (render_pass=0x55a230803f00, options=0x7ffdbca99830) at ../subprojects/wlroots/render/pass.c:34
#7  0x000055a22284c418 in wlr_scene_output_build_state (scene_output=0x55a23073d330, state=0x55a23076b288, options=0x7ffdbca99940) at ../subprojects/wlroots/types/scene/wlr_scene.c:2285
#8  0x000055a2227e51a6 in lab_wlr_scene_output_commit (scene_output=0x55a23073d330, state=0x55a23076b288) at ../src/common/scene-helpers.c:125
#9  0x000055a2227c2ea4 in handle_output_frame (listener=0x55a23076b3d8, data=0x55a230721520) at ../src/output.c:148
#10 0x00007fad8859ab4c in wl_signal_emit_mutable () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#11 0x000055a2228423e3 in wlr_output_send_frame (output=0x55a230721520) at ../subprojects/wlroots/types/output/output.c:804
#12 0x000055a222842427 in schedule_frame_handle_idle_timer (data=0x55a230721520) at ../subprojects/wlroots/types/output/output.c:812
#13 0x00007fad8859cb23 in wl_event_loop_dispatch_idle () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#14 0x00007fad8859cd52 in wl_event_loop_dispatch () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#15 0x00007fad8859a525 in wl_display_run () at /lib/x86_64-linux-gnu/libwayland-server.so.0
#16 0x000055a2227c280e in main (argc=1, argv=0x7ffdbca9a898) at ../src/main.c:273

I have a sigaction sigsetjmp patch that works but this won't get mainlined.