Using rendy on multiple threads at same time causes segfault

[azriel91]

Symptom

Given:

• 2 or more threads
• each thread uses rendy at the same time

Then sometimes one thread's resource cleanup interferes with the other thread's usage.

Steps to Reproduce

This crate just has 100 test functions with an empty GraphBuilder

git clone git@github.com:azriel91/amethyst_rendy_test.git
cd amethyst_rendy_test
cargo update # in case you already had it
cargo test -- --nocapture
# should segfault, if not run it again

# proof that it doesn't segfault with 1 thread:
cargo test -- --nocapture --test-threads 1

Theory

Multiple threads share a common "memory space" (? I don't understand rendy enough). When one is cleaning up, another might be setting up, causing Terminal to be disposed while some Escape values are created.

Note:

When run single threaded (cargo test -- --test-threads 1) with the empty graph, it doesn't segfault.
Further evidence that rendy is correctly disposing in the correct order if you follow the serial control flow.

When run single threaded with RenderTestBundle, which has the sprites and PresentNode in the graph, it does segfault.

Logs

...
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_memory::allocator::dynamic] Memory leak: SizeEntry(8192) is still used
[ERROR][rendy_memory::allocator::dynamic] Memory leak: SizeEntry(1024) is still used
[ERROR][rendy_memory::allocator::dynamic] Memory leak: SizeEntry(65536) is still used
[ERROR][rendy_memory::allocator::dynamic] Memory leak: SizeEntry(524288) is still used
[ERROR][rendy_memory::allocator::dynamic] Memory leak: SizeEntry(4194304) is still used
[ERROR][rendy_resource::escape] `Escape` was dropped after a `Terminal`?
...

Environment

• OS: Windows
• Rendy version: master

[zakarumych]

Cleanup methods require exclusive access to factory.
If you create separate factories then rendy share nothing, except atomic integer to generate ids, but backend can share something.

[crsaracco]

Not sure how related this is, but I also got this while generating meshes and materials. Would something like this run in multiple threads?

struct GameState;
impl SimpleState for GameState {
    fn on_start(&mut self, state_data: StateData<'_, GameData<'_, '_>>) {
        initialize_camera(state_data.world);

        for x in -1..2 {
            for y in -1..2 {
                for z in -1..2 {
                    initialize_cube(state_data.world, x as f32 * 3.0, y as f32 * 3.0, z as f32 * 3.0);
                }
            }
        }

        initialize_light(state_data.world);
    }
}

fn initialize_cube(world: &mut World, x: f32, y: f32, z: f32) {
    let mesh = world.exec(|loader: AssetLoaderSystemData<'_, Mesh>| {
        loader.load_from_data(
            Shape::Cube
                .generate::<(Vec<Position>, Vec<Normal>, Vec<Tangent>, Vec<TexCoord>)>(None)
                .into(),
            (),
        )
    });

    let albedo = material_generator::albedo(world, 1.0, 0.0, 0.0, 1.0);
    let metallic_roughness = material_generator::metallic_roughness(world, 0.5, 0.5);
    let material = material_generator::generate_material(world, albedo, metallic_roughness);

    let mut transform = Transform::default();
    transform.set_translation_xyz(x, y, z);

    world
        .create_entity()
        .with(mesh)
        .with(material)
        .with(transform)
        .build();
}

// `metallic_roughness` and `generate_material` look similar
pub fn albedo(world: &mut World, red: f32, green: f32, blue: f32, alpha: f32) -> Handle<Texture> {
    let albedo = world.exec(|loader: AssetLoaderSystemData<'_, Texture>| {
        loader.load_from_data(
            load_from_linear_rgba(LinSrgba::new(red, green, blue, alpha)).into(),
            (),
        )
    });
    albedo
}

[carnoxen]

Hi, I want to ask for an error. I compiled this project, but got this error ⬇

[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s
[ERROR][rendy_resource::escape] Terminal must be dropped after all `Escape`s

It seems related about this issue, so is there anything for fixing this?

[fu5ha]

That's not the actual error, just symptoms of it. If the application doesn't exit cleanly for whatever reason (a panic most likely) then that will get printed at the end of the log because the graphics resources didn't get cleaned up properly.

…

On Sun, Aug 23, 2020, 4:47 AM Kaben ***@***.***> wrote: Hi, I want to ask for an error. I compiled this project <https://github.com/Temeez/Tiled-Amethyst-Example>, but got this error ⬇ ''' [ERROR][rendy_resource::escape] Terminal must be dropped after all Escapes [ERROR][rendy_resource::escape] Terminal must be dropped after all Escapes [ERROR][rendy_resource::escape] Terminal must be dropped after all Escapes [ERROR][rendy_resource::escape] Terminal must be dropped after all Escapes [ERROR][rendy_resource::escape] Terminal must be dropped after all Escapes [ERROR][rendy_resource::escape] Terminal must be dropped after all Escapes ''' It seems related about this issue, so is there anything for fixing this? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#151 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGYXH7QIYYNM5NJAAWF4B3SCD6VVANCNFSM4HPX2UMQ> .