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CEF ICU FD Crash on Linux During SDL3 Migration ​

Date: February 25, 2026

Summary ​

When running browser surfaces (for example SPACE_BROWSER_CUBE_DEMO=1), the app crashed with Chromium's ICU startup error:

[ERROR:base/i18n/icu_util.cc:232] Invalid file descriptor to ICU data received.
Trace/breakpoint trap (core dumped)

This did not reproduce on plain startup when no browser surface was created, because CEF initialization is lazy.

Reproduction ​

From repo root:

bash
SPACE_DISABLE_AUDIO=1 SPACE_ASSETS_PATH=$(pwd)/assets SPACE_BROWSER_CUBE_DEMO=1 ./build/space -m main

Expected bad behavior before fix:

  • process exits with signal SIGTRAP / code 133
  • ICU FD error appears

Root Cause ​

CEF/Chromium attempted to load icudtl.dat from the directory containing libcef.so:

  • ${SPACE_CEF_ROOT}/Release/icudtl.dat

But in our fetched CEF layout, ICU and other runtime payload files were only in:

  • ${SPACE_CEF_ROOT}/Resources/

So Chromium failed to initialize ICU data and aborted.

Fix Implemented ​

1) Stage runtime payloads next to libcef.so ​

File: cmake/cef.cmake

At configure time, copy these files from Resources/ to Release/ if present:

  • icudtl.dat
  • resources.pak
  • v8_context_snapshot.bin
  • snapshot_blob.bin
  • chrome_100_percent.pak
  • chrome_200_percent.pak
  • locales/

This aligns with Chromium's runtime lookup behavior on Linux.

2) Harden Linux CEF subprocess switches ​

File: src/cef_runtime.cpp

Ensure command-line switches include:

  • no-sandbox
  • disable-setuid-sandbox
  • no-zygote

This prevents sandbox/zygote paths that were not appropriate for this runtime configuration.

Verification ​

Runtime ​

bash
SPACE_DISABLE_AUDIO=1 SPACE_ASSETS_PATH=$(pwd)/assets SPACE_BROWSER_CUBE_DEMO=1 ./build/space -m main

After fix: app starts normally (no ICU FD crash).

Tests ​

  • make test passes
  • make test-e2e passes (after expected SDL3-related snapshot updates)
  • CTest no longer forces SPACE_SKIP_CEF=1 for space_fnl_tests or test_dotenv_integration; both now pass with default CEF startup enabled.

Notes ​

  • This incident is distinct from snapshot differences introduced by SDL3 migration.
  • Snapshot mismatches were visual regressions/golden drift, not CEF startup failures.

See also ​