Segfault is happening in 3.x x86_64 builds on Ubuntu 20.04. aarch64 builds do not exhibit this problem. Ubuntu22 via WSL does not segfault. We are standardized on Ubuntu 20.04 internally. So this is a high priority issue for us (Toyota).

Build flags:
--unoptimized --runtime-mode debug --no-goma --lto --clang --embedder-for-target --full-dart-sdk --target-os linux --linux-cpu x64 --target-triple x86_64-linux-gnu

Repro happens with or without --unoptimized.

Seg fault happens with: https://github.com/freetype/freetype/blob/3f83daeecb1a78d851b660eed025eeba362c0e4a/src/base/ftobjs.c#L5656

The function that calls it has this note:
https://github.com/freetype/freetype/blob/3f83daeecb1a78d851b660eed025eeba362c0e4a/include/freetype/ftcolor.h#L1620

@SInCE: * 2.11 -- currently experimental only! There might be changes without retaining backward compatibility of both the API and ABI.

It looks like it happens when it is trying to display the hello world text: "Futter Demo Home Page"
https://github.com/google/skia/blob/main/modules/skparagraph/src/OneLineShaper.cpp#L705

Full stack trace is documented here:
meta-flutter/flutter_embedded#46

@aikalant