ensure safety of indirect dispatch

by injecting a compute shader that validates the content of the indirect buffer

tests/tests/dispatch_workgroups_indirect.rs

@@ -0,0 +1,155 @@
+use wgpu_test::{gpu_test, FailureCase, GpuTestConfiguration, TestParameters, TestingContext};
+
+/// Make sure that the num_workgroups builtin works properly (it requires a workaround on D3D12).
+#[gpu_test]
+static NUM_WORKGROUPS_BUILTIN: GpuTestConfiguration = GpuTestConfiguration::new()
+    .parameters(
+        TestParameters::default()
+            .downlevel_flags(
+                wgpu::DownlevelFlags::COMPUTE_SHADERS | wgpu::DownlevelFlags::INDIRECT_EXECUTION,
+            )
+            .limits(wgpu::Limits::downlevel_defaults())
+            .expect_fail(FailureCase::backend(wgt::Backends::DX12)),
+    )
+    .run_async(|ctx| async move {
+        let num_workgroups = [1, 2, 3];
+        let res = run_test(&ctx, &num_workgroups, false).await;
+        assert_eq!(res, num_workgroups);
+    });
+
+/// Make sure that we discard (don't run) the dispatch if its size exceeds the device limit.
+#[gpu_test]
+static DISCARD_DISPATCH: GpuTestConfiguration = GpuTestConfiguration::new()
+    .parameters(
+        TestParameters::default()
+            .downlevel_flags(
+                wgpu::DownlevelFlags::COMPUTE_SHADERS | wgpu::DownlevelFlags::INDIRECT_EXECUTION,
+            )
+            .limits(wgpu::Limits {
+                max_compute_workgroups_per_dimension: 10,
+                ..wgpu::Limits::downlevel_defaults()
+            }),
+    )
+    .run_async(|ctx| async move {
+        let max = ctx.device.limits().max_compute_workgroups_per_dimension;
+        let res = run_test(&ctx, &[max + 1, 1, 1], false).await;
+        assert_eq!(res, [0; 3]);
+    });
+
+/// Make sure that unsetting the bind group set by the validation code works properly.
+#[gpu_test]
+static UNSET_INTERNAL_BIND_GROUP: GpuTestConfiguration = GpuTestConfiguration::new()
+    .parameters(
+        TestParameters::default()
+            .downlevel_flags(
+                wgpu::DownlevelFlags::COMPUTE_SHADERS | wgpu::DownlevelFlags::INDIRECT_EXECUTION,
+            )
+            .limits(wgpu::Limits::downlevel_defaults()),
+    )
+    .run_async(|ctx| async move {
+        ctx.device.push_error_scope(wgpu::ErrorFilter::Validation);
+
+        let _ = run_test(&ctx, &[0, 0, 0], true).await;
+
+        let error = pollster::block_on(ctx.device.pop_error_scope());
+        assert!(error.map_or(false, |error| format!("{error}")
+            .contains("Expected bind group is missing")));
+    });
+
+async fn run_test(
+    ctx: &TestingContext,
+    num_workgroups: &[u32; 3],
+    forget_to_set_bind_group: bool,
+) -> [u32; 3] {
+    const SHADER_SRC: &str = "
+        @group(0) @binding(0)
+        var<storage, read_write> out: vec3<u32>;
+
+        @compute @workgroup_size(1)
+        fn main(@builtin(num_workgroups) num_workgroups: vec3<u32>, @builtin(workgroup_id) workgroup_id: vec3<u32>) {
+            if (all(workgroup_id == vec3<u32>())) {
+                out = num_workgroups;
+            }
+        }
+    ";
+
+    let module = ctx
+        .device
+        .create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: None,
+            source: wgpu::ShaderSource::Wgsl(SHADER_SRC.into()),
+        });
+
+    let pipeline = ctx
+        .device
+        .create_compute_pipeline(&wgpu::ComputePipelineDescriptor {
+            label: None,
+            layout: None,
+            module: &module,
+            entry_point: "main",
+            compilation_options: Default::default(),
+            cache: None,
+        });
+
+    let out_buffer = ctx.device.create_buffer(&wgpu::BufferDescriptor {
+        label: None,
+        size: 12,
+        usage: wgpu::BufferUsages::STORAGE | wgpu::BufferUsages::COPY_SRC,
+        mapped_at_creation: false,
+    });
+
+    let readback_buffer = ctx.device.create_buffer(&wgpu::BufferDescriptor {
+        label: None,
+        size: 12,
+        usage: wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::MAP_READ,
+        mapped_at_creation: false,
+    });
+
+    let indirect_buffer = ctx.device.create_buffer(&wgpu::BufferDescriptor {
+        label: None,
+        size: 12,
+        usage: wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::INDIRECT,
+        mapped_at_creation: false,
+    });
+
+    ctx.queue
+        .write_buffer(&indirect_buffer, 0, bytemuck::bytes_of(num_workgroups));
+
+    let bind_group = ctx.device.create_bind_group(&wgpu::BindGroupDescriptor {
+        label: None,
+        layout: &pipeline.get_bind_group_layout(0),
+        entries: &[wgpu::BindGroupEntry {
+            binding: 0,
+            resource: out_buffer.as_entire_binding(),
+        }],
+    });
+
+    let mut encoder = ctx
+        .device
+        .create_command_encoder(&wgpu::CommandEncoderDescriptor::default());
+
+    {
+        let mut compute_pass = encoder.begin_compute_pass(&wgpu::ComputePassDescriptor::default());
+        compute_pass.set_pipeline(&pipeline);
+        if !forget_to_set_bind_group {
+            compute_pass.set_bind_group(0, &bind_group, &[]);
+        }
+        compute_pass.dispatch_workgroups_indirect(&indirect_buffer, 0);
+    }
+
+    encoder.copy_buffer_to_buffer(&out_buffer, 0, &readback_buffer, 0, 12);
+
+    ctx.queue.submit(Some(encoder.finish()));
+
+    readback_buffer
+        .slice(..)
+        .map_async(wgpu::MapMode::Read, |_| {});
+
+    ctx.async_poll(wgpu::Maintain::wait())
+        .await
+        .panic_on_timeout();
+
+    let view = readback_buffer.slice(..).get_mapped_range();
+
+    bytemuck::from_bytes::<[u32; 3]>(&view).to_owned()
+}

tests/tests/root.rs

@@ -14,6 +14,7 @@ mod clear_texture;
 mod compute_pass_resource_ownership;
 mod create_surface_error;
 mod device;
+mod dispatch_workgroups_indirect;
 mod encoder;
 mod external_texture;
 mod float32_filterable;

wgpu-core/src/command/bind.rs

@@ -131,7 +131,7 @@ mod compat {
                         diff.push(format!("Expected {expected_bgl_type} bind group layout, got {assigned_bgl_type}"))
                     }
                 } else {
-                    diff.push("Assigned bind group layout not found (internal error)".to_owned());
+                    diff.push("Expected bind group is missing".to_owned());
                 }
             } else {
                 diff.push("Expected bind group layout not found (internal error)".to_owned());
@@ -191,6 +191,10 @@ mod compat {
             self.make_range(index)
         }
 
+        pub fn unassign(&mut self, index: usize) {
+            self.entries[index].assigned = None;
+        }
+
         pub fn list_active(&self) -> impl Iterator<Item = usize> + '_ {
             self.entries
                 .iter()
@@ -358,6 +362,14 @@ impl<A: HalApi> Binder<A> {
         &self.payloads[bind_range]
     }
 
+    pub(super) fn unassign_group(&mut self, index: usize) {
+        log::trace!("\tBinding [{}] = null", index);
+
+        self.payloads[index].reset();
+
+        self.manager.unassign(index);
+    }
+
     pub(super) fn list_active<'a>(&'a self) -> impl Iterator<Item = &'a Arc<BindGroup<A>>> + '_ {
         let payloads = &self.payloads;
         self.manager