`CustomGeometrySource.Grid` test crash on Linux (`MLN_USE_RUST=ON`)

[louwers]

I am seeing CustomGeometrySource.Grid crashing on Linux on multiple unrelated PRs.

#3389

#3373

#3384

[louwers]

Turns out it's only the Rust build that is segfaulting on CI.

Couldn't reproduce it locally. I have disabled the Rust build in linux-ci.yml for now. 88fd774#diff-9a8a3273e0db8ac68a2678dbb9daa2570f98e94773070e4cc4c4a89b081e5d9f

cc @nyurik

[nyurik]

Are you saying something has changed since we introduced it? I think all CI was passing just fine before

[louwers]

Yes it was passing before...

[nyurik]

ok, so did CI fail to block a change that causes segfault? Was it intermittent?

[louwers]

@nyurik It started failing for several unreleated PRs.

[nyurik]

I did a deep dive into this. It seems it fails for all commits ever since rust was added in 527e70b (#3137). For testing, I used mbgl-test-runner which initially was placed at ./build/ dir:

build-linux-opengl/mbgl-test-runner --gtest_filter=CustomGeometrySource.Grid

It always segfaults. I also tried building it with an old 1.70 Rust compiler, with the same result.

Still unknown how it was possible for this to ever pass CI...? Do we have a recent CI run that passes this test?

[nyurik]

It seems this is still related to rust, but I have no idea how CI was passing it before

❯ lldb-18 build-linux-opengl/mbgl-test-runner -- --gtest_filter=CustomGeometrySource.Grid
(lldb) target create "build-linux-opengl/mbgl-test-runner"
Current executable set to '/home/nyurik/dev/maplibre/just-maplibre-native/maplibre-native/build-linux-opengl/mbgl-test-runner' (x86_64).
(lldb) settings set -- target.run-args  "--gtest_filter=CustomGeometrySource.Grid"
(lldb) run
Process 581255 launched: '/home/nyurik/dev/maplibre/just-maplibre-native/maplibre-native/build-linux-opengl/mbgl-test-runner' (x86_64)
Note: Google Test filter = CustomGeometrySource.Grid
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from CustomGeometrySource
[ RUN      ] CustomGeometrySource.Grid
Process 581255 stopped
* thread #1, name = 'mbgl-test-runne', stop reason = signal SIGSEGV: address not mapped to object (fault address: 0x3)
    frame #0: 0x0000555555e943df mbgl-test-runner`rustutils$cxxbridge1$parse_css_color + 111
mbgl-test-runner`rustutils$cxxbridge1$parse_css_color:
->  0x555555e943df <+111>: movzbl (%rcx), %r10d
    0x555555e943e3 <+115>: testb  %r10b, %r10b
    0x555555e943e6 <+118>: js     0x555555e94400 ; <+144>

I was able to compile this with docker as well, using my https://github.com/nyurik/just-maplibre-native with sub-dir having the latest main branch of MLN:

just init-docker
just init-cmake
just cmake-build mbgl-test-runner
build-linux-opengl/mbgl-test-runner --gtest_filter=CustomGeometrySource.Grid

[louwers]

Unfortunately I cannot reproduce it, not on macOS, not on a Linux box and not with Docker.