Cog keeps crashing #758
Description
Hello, folks! I'm very much a novice to Linux, WebKit and Cog.
I've been trying to get a simple Buildroot setup working with Cog using DRM and while I've cleared a fair few hurdles to even get this far, Cog simply refuses to render anything and keeps crashing:
(cog:347): Cog-Core-CRITICAL **: 18:09:11.062: The renderer process crashed, exiting...
I don't know what else to do and I'm unsure how to debug this. I'm looking for any hints or pointers that can set me on the right path.
My setup:
- Raspberry Pi 5 with 8GB RAM
- OS: Buildroot (2025.05)
- Cog (0.18.4)
- WPE WebKit (2.44.4)
I believe I have all the require packages enabled (showing just the relevant ones) in my defconfig
# WPE Webkit and cog
BR2_PACKAGE_WPEWEBKIT=y
BR2_PACKAGE_COG=y
BR2_PACKAGE_WPEBACKEND_FDO=y
BR2_PACKAGE_COG_PLATFORM_DRM=y
BR2_PACKAGE_COG_PLATFORM_FDO=n
BR2_PACKAGE_EUDEV=y
# glib might need for mime types?
# and won't load local pages without? dunno...
BR2_PACKAGE_SHARED_MIME_INFO=y
# A lack of fonts can cause webkit crashes? Bruh...
BR2_PACKAGE_BITSTREAM_VERA=y
# Serving built react/vite app locally
BR2_PACKAGE_LIGHTTPD=y
# GPU related
BR2_PACKAGE_MESA3D=y
BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_V3D=y
BR2_PACKAGE_MESA3D_OPENGL_ES=y
In my cog-env.sh file I do the following:
#!/bin/sh
# Set base cog parameters. I flippin hope these work.
export COG_PLATFORM_NAME=drm
export EGL_PLATFORM=drm # need to explicitly tell EGL to use drm? dunno, undocumented...
# Create runtime directory with proper permissions
export XDG_RUNTIME_DIR=/run/user/0
mkdir -p "$XDG_RUNTIME_DIR"
chmod 0700 "$XDG_RUNTIME_DIR"
# Ensure proper device permissions
chmod 666 /dev/dri/card0 2>/dev/null || true
chmod 666 /dev/dri/renderD128 2>/dev/null || true
chmod 666 /dev/input/* 2>/dev/null || true
I've also had to set up these symlinks in my post-build.sh cause apparently webkit/cog (I don't remember) couldn't find the correct things:
# Create OpenGL symlinks for compatibility
echo "Creating OpenGL compatibility symlinks..."
# For libGL.so.1 (Using GLESv2 as the implementation)
if [ -f "${TARGET_DIR}/usr/lib/libGLESv2.so" ] && [ ! -f "${TARGET_DIR}/usr/lib/libGL.so.1" ]; then
ln -sf libGLESv2.so ${TARGET_DIR}/usr/lib/libGL.so.1
ln -sf libGLESv2.so ${TARGET_DIR}/usr/lib/libGL.so
echo "Created libGL.so.1 -> libGLESv2.so symlink"
fi
# For libOpenGL.so.0 (Using EGL as the implementation)
if [ -f "${TARGET_DIR}/usr/lib/libEGL.so" ] && [ ! -f "${TARGET_DIR}/usr/lib/libOpenGL.so.0" ]; then
ln -sf libEGL.so ${TARGET_DIR}/usr/lib/libOpenGL.so.0
ln -sf libEGL.so ${TARGET_DIR}/usr/lib/libOpenGL.so
echo "Created libOpenGL.so.0 -> libEGL.so symlink"
fi
# Make sure cog can run
chmod +x "${TARGET_DIR}/etc/profile.d/cog-env.sh"
Lastly, my config.txt has the correct overlay set for the Pi and some screen related flags (a Waveshare HDMI touch display):
# GPU memory allocation - important for WPE/COG
gpu_mem_1024
# Enable VC4/V3D driver with full KMS
dtoverlay=vc4-kms-v3d
max_framebuffers=2
# Force HDMI mode even if no HDMI monitor detected
hdmi_force_hotplug=1
# Setting for display
hdmi_group=2
hdmi_mode=87
hdmi_cvt 1280 800 60 6 0 0 0
hdmi_drive=1
I then try to run Cog in the terminal like such (I've added url related flags based on this issue):
G_MESSAGES_DEBUG=all cog --platform=drm --platform-params="renderer=gles" --webprocess-failure=exit --enable-write-console-messages-to-stdout=true --allow-file-access-from-file-urls=true --allow-universal-access-from-file-urls=true file:///www/index.html
I've ran out of ideas. It doesn't matter whether it's a local file or a URL, it simply keeps crashing. I don't know if there is some requirement I've yet to meet or there's a missing package. No clue. I wish there was documentation for this. If there is, can someone please point me to it?
Any help super appreciated. I've been at it for days now, lol...