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Fix that memory for struct data was released before wgpu-native consumed it #765

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merged 1 commit into from
Nov 5, 2025
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Fix that memory for struct data was released before wgpu-native consumed it #765

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60 changes: 42 additions & 18 deletions wgpu/backends/wgpu_native/_api.py
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Original file line number Diff line number Diff line change
Expand Up @@ -334,10 +334,14 @@ def _get_limits(id: int, device: bool = False, adapter: bool = False):
# not used: maxPushConstantSize
# not used: maxNonSamplerBindings
)

# Note that the object returned by ffi.cast() does not own the memory, so we must keep a ref to the uncast object, until wgpu-native has consumed it.
c_limit_next_in_chain = ffi.addressof(c_limits_native, "chain")

# H: nextInChain: WGPUChainedStructOut *, maxTextureDimension1D: int, maxTextureDimension2D: int, maxTextureDimension3D: int, maxTextureArrayLayers: int, maxBindGroups: int, maxBindGroupsPlusVertexBuffers: int, maxBindingsPerBindGroup: int, maxDynamicUniformBuffersPerPipelineLayout: int, maxDynamicStorageBuffersPerPipelineLayout: int, maxSampledTexturesPerShaderStage: int, maxSamplersPerShaderStage: int, maxStorageBuffersPerShaderStage: int, maxStorageTexturesPerShaderStage: int, maxUniformBuffersPerShaderStage: int, maxUniformBufferBindingSize: int, maxStorageBufferBindingSize: int, minUniformBufferOffsetAlignment: int, minStorageBufferOffsetAlignment: int, maxVertexBuffers: int, maxBufferSize: int, maxVertexAttributes: int, maxVertexBufferArrayStride: int, maxInterStageShaderVariables: int, maxColorAttachments: int, maxColorAttachmentBytesPerSample: int, maxComputeWorkgroupStorageSize: int, maxComputeInvocationsPerWorkgroup: int, maxComputeWorkgroupSizeX: int, maxComputeWorkgroupSizeY: int, maxComputeWorkgroupSizeZ: int, maxComputeWorkgroupsPerDimension: int
c_limits = new_struct_p(
"WGPULimits *",
nextInChain=ffi.addressof(c_limits_native, "chain"),
nextInChain=c_limit_next_in_chain,
# not used: maxTextureDimension1D
# not used: maxTextureDimension2D
# not used: maxTextureDimension3D
Expand Down Expand Up @@ -1214,12 +1218,15 @@ def canonicalize_limit_name(name):
c_trace_path = to_c_string_view(trace_path if trace_path else None)

# H: chain: WGPUChainedStruct, tracePath: WGPUStringView
extras = new_struct_p(
c_device_extras = new_struct_p(
"WGPUDeviceExtras *",
tracePath=c_trace_path,
# not used: chain
)
extras.chain.sType = lib.WGPUSType_DeviceExtras
c_device_extras.chain.sType = lib.WGPUSType_DeviceExtras

# Note that the object returned by ffi.cast() does not own the memory, so we must keep a ref to the uncast object, until wgpu-native has consumed it.
c_device_next_in_chain = ffi.cast("WGPUChainedStruct * ", c_device_extras)

# ----- Device lost

Expand Down Expand Up @@ -1277,7 +1284,7 @@ def uncaptured_error_callback(
# H: nextInChain: WGPUChainedStruct *, label: WGPUStringView, requiredFeatureCount: int, requiredFeatures: WGPUFeatureName *, requiredLimits: WGPULimits *, defaultQueue: WGPUQueueDescriptor, deviceLostCallbackInfo: WGPUDeviceLostCallbackInfo, uncapturedErrorCallbackInfo: WGPUUncapturedErrorCallbackInfo
struct = new_struct_p(
"WGPUDeviceDescriptor *",
nextInChain=ffi.cast("WGPUChainedStruct * ", extras),
nextInChain=c_device_next_in_chain,
label=to_c_string_view(label),
requiredFeatureCount=len(c_features),
requiredFeatures=new_array("WGPUFeatureName[]", c_features),
Expand Down Expand Up @@ -1708,7 +1715,7 @@ def _create_pipeline_layout(
bind_group_layouts_ids = [x._internal for x in bind_group_layouts]
c_layout_array = new_array("WGPUBindGroupLayout[]", bind_group_layouts_ids)

next_in_chain = ffi.NULL
c_pipeline_layout_next_in_chain = ffi.NULL
if push_constant_layouts:
count = len(push_constant_layouts)
c_push_constant_ranges = new_array("WGPUPushConstantRange[]", count)
Expand All @@ -1730,12 +1737,15 @@ def _create_pipeline_layout(
# not used: chain
)
c_pipeline_layout_extras.chain.sType = lib.WGPUSType_PipelineLayoutExtras
next_in_chain = ffi.cast("WGPUChainedStruct *", c_pipeline_layout_extras)
# Note that the object returned by ffi.cast() does not own the memory, so we must keep a ref to the uncast object, until wgpu-native has consumed it.
c_pipeline_layout_next_in_chain = ffi.cast(
"WGPUChainedStruct *", c_pipeline_layout_extras
)

# H: nextInChain: WGPUChainedStruct *, label: WGPUStringView, bindGroupLayoutCount: int, bindGroupLayouts: WGPUBindGroupLayout *
struct = new_struct_p(
"WGPUPipelineLayoutDescriptor *",
nextInChain=next_in_chain,
nextInChain=c_pipeline_layout_next_in_chain,
label=to_c_string_view(label),
bindGroupLayouts=c_layout_array,
bindGroupLayoutCount=len(bind_group_layouts),
Expand Down Expand Up @@ -1829,10 +1839,13 @@ def create_shader_module(
"Shader code must be str for WGSL or GLSL, or bytes for SpirV."
)

# Note that the object returned by ffi.cast() does not own the memory, so we must keep a ref to the uncast object, until wgpu-native has consumed it.
c_shader_module_next_in_chain = ffi.cast("WGPUChainedStruct *", source_struct)

# H: nextInChain: WGPUChainedStruct *, label: WGPUStringView
struct = new_struct_p(
"WGPUShaderModuleDescriptor *",
nextInChain=ffi.cast("WGPUChainedStruct *", source_struct),
nextInChain=c_shader_module_next_in_chain,
label=to_c_string_view(label),
)
# H: WGPUShaderModule f(WGPUDevice device, WGPUShaderModuleDescriptor const * descriptor)
Expand Down Expand Up @@ -1964,7 +1977,7 @@ def create_render_pipeline(
) -> GPURenderPipeline:
primitive = {} if primitive is None else primitive
multisample = {} if multisample is None else multisample
descriptor = self._create_render_pipeline_descriptor(
descriptor, _keep_alive = self._create_render_pipeline_descriptor(
label, layout, vertex, primitive, depth_stencil, multisample, fragment
)
# H: WGPURenderPipeline f(WGPUDevice device, WGPURenderPipelineDescriptor const * descriptor)
Expand All @@ -1985,7 +1998,7 @@ def create_render_pipeline_async(
primitive = {} if primitive is None else primitive
multisample = {} if multisample is None else multisample
# TODO: wgpuDeviceCreateRenderPipelineAsync is not yet implemented in wgpu-native
descriptor = self._create_render_pipeline_descriptor(
descriptor, _keep_alive = self._create_render_pipeline_descriptor(
label, layout, vertex, primitive, depth_stencil, multisample, fragment
)

Expand Down Expand Up @@ -2051,6 +2064,9 @@ def _create_render_pipeline_descriptor(
multisample: structs.MultisampleState,
fragment: structs.FragmentState,
):
# We need to keep some objects alive until the struct is consumed by wgpu-native
keep_alive = []

depth_stencil = depth_stencil or {}
multisample = multisample or {}
primitive = primitive or {}
Expand Down Expand Up @@ -2098,12 +2114,17 @@ def _create_render_pipeline_descriptor(
conservative=primitive_extras.get("conservative", False),
)
c_primitive_state_extras.chain.sType = lib.WGPUSType_PrimitiveStateExtras
next_in_chain = ffi.cast("WGPUChainedStruct *", c_primitive_state_extras)

# Note that the object returned by ffi.cast() does not own the memory, so we must keep a ref to the uncast object, until wgpu-native has consumed it.
c_primitive_state_next_in_chain = ffi.cast(
"WGPUChainedStruct *", c_primitive_state_extras
)
keep_alive.append(c_primitive_state_extras)

# H: nextInChain: WGPUChainedStruct *, topology: WGPUPrimitiveTopology, stripIndexFormat: WGPUIndexFormat, frontFace: WGPUFrontFace, cullMode: WGPUCullMode, unclippedDepth: WGPUBool/int
c_primitive_state = new_struct(
"WGPUPrimitiveState",
nextInChain=next_in_chain,
nextInChain=c_primitive_state_next_in_chain,
topology=primitive.get("topology", "triangle-list"),
stripIndexFormat=primitive.get("strip_index_format", 0),
frontFace=primitive.get("front_face", "ccw"),
Expand Down Expand Up @@ -2170,7 +2191,7 @@ def _create_render_pipeline_descriptor(
multisample=c_multisample_state,
fragment=c_fragment_state,
)
return struct
return struct, keep_alive

def _create_color_target_state(self, target):
if not target.get("blend", None):
Expand Down Expand Up @@ -2332,27 +2353,30 @@ def _create_statistics_query_set(self, label, count, statistics):
)

def _create_query_set(self, label, type, count, statistics):
next_in_chain = ffi.NULL
c_query_set_next_in_chain = ffi.NULL
if statistics:
c_statistics = new_array("WGPUPipelineStatisticName[]", statistics)
# H: chain: WGPUChainedStruct, pipelineStatistics: WGPUPipelineStatisticName *, pipelineStatisticCount: int
query_set_descriptor_extras = new_struct_p(
c_query_set_descriptor_extras = new_struct_p(
"WGPUQuerySetDescriptorExtras *",
pipelineStatisticCount=len(statistics),
pipelineStatistics=ffi.cast(
"WGPUPipelineStatisticName const *", c_statistics
),
# not used: chain
)
query_set_descriptor_extras.chain.sType = (
c_query_set_descriptor_extras.chain.sType = (
lib.WGPUSType_QuerySetDescriptorExtras
)
next_in_chain = ffi.cast("WGPUChainedStruct *", query_set_descriptor_extras)
# Note that the object returned by ffi.cast() does not own the memory, so we must keep a ref to the uncast object, until wgpu-native has consumed it.
c_query_set_next_in_chain = ffi.cast(
"WGPUChainedStruct *", c_query_set_descriptor_extras
)

# H: nextInChain: WGPUChainedStruct *, label: WGPUStringView, type: WGPUQueryType, count: int
query_set_descriptor = new_struct_p(
"WGPUQuerySetDescriptor *",
nextInChain=next_in_chain,
nextInChain=c_query_set_next_in_chain,
label=to_c_string_view(label),
type=type,
count=count,
Expand Down
4 changes: 3 additions & 1 deletion wgpu/backends/wgpu_native/_helpers.py
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Original file line number Diff line number Diff line change
Expand Up @@ -95,11 +95,13 @@ def get_wgpu_instance(extras=None):
raise RuntimeError(
"Instance already exists. Please call `set_instance_extras` before the instance is created (calls to `request_adapter` or `enumerate_adapters`)"
)

if _the_instance is None:
# H: nextInChain: WGPUChainedStruct *
struct = ffi.new("WGPUInstanceDescriptor *")
if extras is not None:
struct.nextInChain = ffi.cast("WGPUChainedStruct *", extras)
c_instance_next_in_chain = ffi.cast("WGPUChainedStruct *", extras)
struct.nextInChain = c_instance_next_in_chain
_the_instance = lib.wgpuCreateInstance(struct)
return _the_instance

Expand Down
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