Memory Leak in QtWebEngine on Limited Hardware

We are experiencing a potential memory leak when running a basic QtWebEngine-based application on hardware with limited RAM (~1GB). The application loads a simple slideshow webpage (a single HTML file with three PNG images in an img/ directory). The image switch interval is set to 0.5 seconds to reproduce the issue more quickly. Upon execution, the application's virtual memory usage grows continuously until the system has only ~35MB of free memory left. At this point, the application becomes extremely slow, with image transitions occurring at ~5-minute intervals, though it does not completely freeze.

Expected Behavior:

• The application should maintain a reasonable memory footprint without excessive virtual memory growth.

• Image transitions should remain smooth and within the expected interval.

Observed Behavior:

• Right after application startup:

PID   VSZ  RSS  COMMAND
14076 1.5g 149m qtwebengine-test
$ free
                       total        used           free         shared    buff/cache   available
Mem:         947.3M      465.4M      151.0M       34.5M      330.9M      381.3M

• After a few minutes:

PID   VSZ  RSS  COMMAND
14076 1.8g  71m qtwebengine-test

$ free
                      total        used            free          shared  buff/cache   available
Mem:         947.3M      812.4M       39.0M       34.9M       96.0M       36.5M

• The system becomes unresponsive but does not completely crash.

Suspected Cause:

• Possible memory leak in QtWebEngine leading to excessive virtual memory growth.
• Potential DOM node leaks or JavaScript heap issues.
• Chromium remote debugging does not confirm JS heap leakage.
• Adjustments to heap size and GC intervals have had no effect.

Reproduction Steps:

1. Run the QtWebEngine-based application on the target hardware.
2. Load the slideshow webpage.
3. Observe memory usage over time.
4. Note that the virtual memory usage increases rapidly until the system is nearly out of memory.

Environment Details:

• Hardware: ~1GB RAM system
• QtWebEngine Version: [Specify version]

• Operating System: [Specify OS]

• Environment Variables:
  **

  QTWEBENGINEPROCESS_PATH=/usr/libexec/QtWebEngineProcess
  QTWEBENGINE_LOCALES_PATH=/usr/share/translations/qtwebengine_locales
  QTWEBENGINE_RESOURCES_PATH=/usr/share/resources
  QT_QPA_PLATFORM=wayland-egl
  USER=root
  XDG_RUNTIME_DIR=/run/wayland-lvds
  QTWEBENGINE_CHROMIUM_FLAGS=--remote-debugging-port=7777 --enable-logging --log-level=0 --v=2 --no-sandbox --enable-aggressive-domstorage-flushing --js-flags="--max-old-space-size=1 --max-semi-space-size=1 --optimize-for-size --gc-interval=1"

  **

Troubleshooting Attempts:

• Monitored memory usage through Chromium remote debugger (no clear heap leaks detected).
• Adjusted QtWebEngine settings to limit heap size and increase garbage collection frequency (no impact observed).

Impact Assessment:

• Application performance degrades significantly over time.
• The issue prevents reliable operation on resource-limited devices.

Next Steps:

• Investigate potential memory leak in QtWebEngine.
• Perform further profiling to determine if DOM nodes are accumulating.
• Validate if issue persists in newer versions of QtWebEngine.
• Consider alternative garbage collection or memory management strategies.