[Impeller] Retry uncompressed when fixed-rate compression is exhausted by rlueders · Pull Request #187586 · flutter/flutter

rlueders · 2026-06-04T20:50:10Z

Issue

On the Pixel 10 (Tensor G5 / Imagination PowerVR GPU), Impeller's Vulkan backend
crashes the raster thread under GPU pressure:

[ERROR:impeller/renderer/backend/vulkan/allocator_vk.cc] Unable to allocate Vulkan Image:
  ErrorCompressionExhaustedEXT Type: Texture2D ... Usage: { ShaderRead, RenderTarget }
[ERROR:impeller/renderer/render_target.cc] Could not create color texture.
[ERROR:impeller/renderer/render_target.cc] Render target does not have color attachment at index 0.
F/libc: Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0 in tid NNNN (1.raster)

(In release builds the same failure surfaces as
[FATAL:flutter/impeller/display_list/canvas.cc(1471)] Check failed: back_texture. Context is valid:0
SIGABRT, or a bare SIGSEGV @ 0x20 on the *.raster thread.)

Root cause

Impeller requests fixed-rate image compression (VkImageCompressionControlEXT) for
lossy render targets (CreateOffscreenMSAA's color-resolve texture). When the PowerVR
driver's fixed-rate-compression resources are exhausted, vmaCreateImage returns
VK_ERROR_COMPRESSION_EXHAUSTED_EXT. AllocatedTextureSourceVK did not handle this — it
logged and returned an invalid texture, which became a render target with no color
attachment, and the raster thread then dereferenced the null texture.

This is a regression: it does not reproduce on Flutter 3.41.9, but does on 3.44.x.
It is PowerVR-specific (the error is tied to the driver's compression resource pool) and
GPU-state-dependent (it fires once cumulative GPU compression pressure is high enough).

Fix

VK_ERROR_COMPRESSION_EXHAUSTED_EXT is, per the Vulkan spec, only returned for fixed-rate
compression requests — so retrying the same allocation without compression is always a
valid recovery. On that error, AllocatedTextureSourceVK now unlinks
VkImageCompressionControlEXT from the create-info chain and retries vmaCreateImage once
uncompressed (logging a one-time warning). The texture is identical, just stored
uncompressed; the only cost is on the failure path (a small amount of extra
memory/bandwidth for the affected texture, instead of a crash).

Tests

Unit test (allocator_vk_unittests.cc → RetriesUncompressedOnCompressionExhausted):
extends the Vulkan mock to advertise fixed-rate compression and to fail the first
compressed vkCreateImage with VK_ERROR_COMPRESSION_EXHAUSTED_EXT, then asserts the
allocator returns a valid texture and called vkCreateImage twice (compressed
attempt + uncompressed retry). Passes; the other allocator tests are unaffected.

On-device A/B (Pixel 10, locally-built android_profile_arm64, same repro, same
GPU-pressured state):

Engine	Result
Unpatched	`ErrorCompressionExhausted` → SIGSEGV on `1.raster` (crash)
Patched	exhaustion → retry → survives; logs `Fixed-rate image compression exhausted; falling back to uncompressed image allocation`

Repro

A pure-Flutter app that stacks enough full-screen BackdropFilter / saveLayer offscreen
render targets to exhaust the PowerVR compression pool (see lib/main.dart in the linked
repro). Crashes on the unpatched engine; runs on the patched one. Stable on either with
--no-enable-impeller.

Environment

Flutter 3.44.x (regressed from 3.41.9)
Device: Pixel 10, Android 17 (API 37)
GPU: Imagination PowerVR (Tensor G5); renderer Impeller / Vulkan

Pre-launch checklist

Added a unit test (or explained why not possible).
Listed any breaking changes (none).
Signed the CLA.

google-cla · 2026-06-04T20:50:26Z

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For the most up to date status, view the checks section at the bottom of the pull request.

On the Pixel 10 (Imagination PowerVR GPU), vmaCreateImage can return VK_ERROR_COMPRESSION_EXHAUSTED_EXT when the driver's fixed-rate image-compression resources are depleted. Impeller requests fixed-rate compression for lossy render targets but did not handle this failure: it returned an invalid texture, producing a render target with no color attachment, which then crashed the raster thread (FML_CHECK(back_texture) / null deref on canvas.cc). Per the Vulkan spec this error is only returned for fixed-rate compression requests, so this retries the image allocation once with VkImageCompressionControlEXT unlinked (uncompressed) -- a valid recovery. Regression first observed between Flutter 3.41.9 and 3.44; stable with --no-enable-impeller. Adds an allocator_vk_unittests case that injects the error via the Vulkan mock (advertising fixed-rate compression support) and verifies the allocator retries and returns a valid texture.

gemini-code-assist

Code Review

This pull request implements a fallback mechanism in the Vulkan allocator to retry image allocation without compression if the initial attempt fails with VK_ERROR_COMPRESSION_EXHAUSTED_EXT. It also updates the mock Vulkan implementation to simulate this error and adds a unit test to verify that the allocator successfully falls back to an uncompressed allocation. There are no review comments, and I have no feedback to provide.

flutter-dashboard · 2026-06-08T18:40:55Z

CI had a failure that stopped further tests from running. We need to investigate to determine the root cause.

SHA at time of execution: b37f7f7.

Possible causes:

Configuration Changes: The .ci.yaml file might have been modified between the creation of this pull request and the start of this test run. This can lead to ci yaml validation errors.
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Error Details:

GitHub Error: You have exceeded a secondary rate limit. Please wait a few minutes before you try again. For more on scraping GitHub and how it may affect your rights, please review our Terms of Service (https://docs.github.com/en/site-policy/github-terms/github-terms-of-service) If you reach out to GitHub Support for help, please include the request ID 997A:193DD0:48BA4FE:11698282:6A270CB6.

Stack trace:

#0      GitHub.handleStatusCode (package:github/src/common/github.dart:486:5)
#1      GitHub.request (package:github/src/common/github.dart:422:7)
<asynchronous suspension>
#2      GitHub.requestJson (package:github/src/common/github.dart:323:22)
<asynchronous suspension>
#3      RetryOptions.retry (package:retry/retry.dart:131:16)
<asynchronous suspension>
#4      LuciBuildService._scheduleTryBuilds (package:cocoon_service/src/service/luci_build_service.dart:307:26)
<asynchronous suspension>
#5      Scheduler._runCiTestingStage (package:cocoon_service/src/service/scheduler.dart:1468:9)
<asynchronous suspension>
#6      Scheduler.proceedToCiTestingStage (package:cocoon_service/src/service/scheduler.dart:1519:7)
<asynchronous suspension>
#7      Scheduler._closeSuccessfulEngineBuildStage (package:cocoon_service/src/service/scheduler.dart:1333:5)
<asynchronous suspension>
#8      Scheduler.processCheckRunCompleted (package:cocoon_service/src/service/scheduler.dart:1265:11)
<asynchronous suspension>
#9      PresubmitLuciSubscription.post (package:cocoon_service/src/request_handlers/presubmit_luci_subscription.dart:176:9)
<asynchronous suspension>
#10     RequestHandler.service (package:cocoon_service/src/request_handling/request_handler.dart:42:20)
<asynchronous suspension>
#11     SubscriptionHandler.service (package:cocoon_service/src/request_handling/subscription_handler.dart:139:5)
<asynchronous suspension>
#12     createServer.<anonymous closure> (package:cocoon_service/server.dart:448:7)
<asynchronous suspension>
#13     main.<anonymous closure>.<anonymous closure> (file:///app/app_dart/bin/gae_server.dart:187:9)
<asynchronous suspension>

gaaclarke

This code looks good to me. The tests are sufficient and the logic seems reasonable considering the runtime error we are getting. I just have a few minor comments on the code. Thanks!

- mock_vulkan: move compression_requested into the while condition - allocator_vk: use explicit types (vk::ImageCreateInfo::NativeType, vk::Result) instead of auto type deduction

gaaclarke

lgtm! thanks

rlueders · 2026-06-08T21:54:04Z

Thanks @gaaclarke. Both of those have been addressed.

gaaclarke · 2026-06-08T21:54:13Z

@jason-simmons want to be a second reviewer on this?

auto-submit · 2026-06-08T23:08:35Z

autosubmit label was removed for flutter/flutter/187586, because - The status or check suite Linux linux_unopt has failed. Please fix the issues identified (or deflake) before re-applying this label.

The status or check suite Google testing has failed. Please fix the issues identified (or deflake) before re-applying this label.

gaaclarke · 2026-06-08T23:18:42Z

The CI failures are apropos:

[0;32m[ RUN      ] �[mGPUSurfaceVulkanImpeller.RecreatesTransientsWhenFrameSizeChanges
[INFO:flutter/testing/test_vulkan_context.cc(41)] Using Vulkan ICD: libvk_swiftshader.so
[WARNING:flutter/common/graphics/persistent_cache.cc(286)] Could not acquire the persistent cache directory. Caching of GPU resources on disk is disabled.
[FATAL:flutter/third_party/vulkan-deps/vulkan-headers/src/include/vulkan/vulkan.hpp(841)] Check failed: false.
[ERROR:flutter/fml/backtrace.cc(108)] Caught signal SIGABRT during program execution.
Frame 0: 0x743d740969fc pthread_kill
Frame 1: 0x743d74042476 gsignal
Frame 2: 0x743d740287f3 abort
Frame 3: 0x60ab8e7bf32e Unknown
Frame 4: 0x60ab8e7bf273 fml::LogMessage::~LogMessage()
Frame 5: 0x60ab9269aba8 impeller::vk::StructureChain<>::unlink()
Frame 6: 0x60ab92697ff5 impeller::vk::StructureChain<>::unlink<>()
Frame 7: 0x60ab9269814e impeller::AllocatedTextureSourceVK::AllocatedTextureSourceVK()::{lambda()#1}::operator()()
Frame 8: 0x60ab9268e382 impeller::AllocatedTextureSourceVK::AllocatedTextureSourceVK()
Frame 9: 0x60ab9268b9b9 std::__fl::construct_at[abi:nn210000]<>()
Frame 10: 0x60ab9268b8dd std::__fl::__construct_at[abi:nn210000]<>()
Frame 11: 0x60ab9268b651 std::__fl::allocator_traits<>::construct[abi:nn210000]<>()
Frame 12: 0x60ab9268b25d std::__fl::__shared_ptr_emplace<>::__shared_ptr_emplace[abi:nn210000]<>()
Frame 13: 0x60ab9268ae04 std::__fl::allocate_shared[abi:nn210000]<>()
Frame 14: 0x60ab926844d9 std::__fl::make_shared[abi:nn210000]<>()
Frame 15: 0x60ab9267f85f impeller::AllocatorVK::OnCreateTexture()
Frame 16: 0x60ab8e752af1 impeller::Allocator::CreateTexture()
Frame 17: 0x60ab9225a5c0 impeller::ContentContext::ContentContext()
Frame 18: 0x60ab92176eca std::__fl::make_unique[abi:nn210000]<>()
Frame 19: 0x60ab92176b13 impeller::AiksContext::AiksContext()
Frame 20: 0x60ab914bb868 std::__fl::construct_at[abi:nn210000]<>()
Frame 21: 0x60ab914bb725 std::__fl::__construct_at[abi:nn210000]<>()
Frame 22: 0x60ab914bb4b9 std::__fl::allocator_traits<>::construct[abi:nn210000]<>()
Frame 23: 0x60ab914bb0e9 std::__fl::__shared_ptr_emplace<>::__shared_ptr_emplace[abi:nn210000]<>()
Frame 24: 0x60ab914baca9 std::__fl::allocate_shared[abi:nn210000]<>()
Frame 25: 0x60ab914b723a std::__fl::make_shared[abi:nn210000]<>()
Frame 26: 0x60ab914a7951 flutter::GPUSurfaceVulkanImpeller::GPUSurfaceVulkanImpeller()

Per review: when the device doesn't support fixed-rate compression the ImageCompressionControlEXT struct is already unlinked above, so having try_create_image unlink it again on the uncompressed path asserted. Drop the use_compression argument; the lambda now allocates with the current create-info chain. Unlink the compression-control struct once, in the retry path, before the uncompressed second attempt.

gaaclarke

lgtm

fluttergithubbot · 2026-06-09T16:37:48Z

An existing Git SHA, 6521ad9b991fe1473fec87d9627cfa12b691051d, was detected, and no actions were taken.

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jtmcdole · 2026-06-09T16:51:42Z

Re-adding the CICD label broke the system. I merged master and re-added the label

flutter/flutter@66aaa9a...c0a1129 2026-06-10 137456488+flutter-pub-roller-bot@users.noreply.github.com Roll pub packages (flutter/flutter#187740) 2026-06-09 burak.karahan@mail.ru Remove Material import from view chrome style test (flutter/flutter#186994) 2026-06-09 jason-simmons@users.noreply.github.com [Impeller] Remove unused DeviceHolderVK reference from CommandBufferVK (flutter/flutter#187705) 2026-06-09 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from KNe93cf5wU4xG2d-m... to 8azSyvz57mKcPqTwk... (flutter/flutter#187745) 2026-06-09 1063596+reidbaker@users.noreply.github.com Add android-agent agent.json and update reidbaker-agent skills (flutter/flutter#187746) 2026-06-09 engine-flutter-autoroll@skia.org Roll Skia from aeed11c35004 to 9f02102df298 (9 revisions) (flutter/flutter#187744) 2026-06-09 bdero@google.com [Impeller] Remove the texture coordinate system Y-flip workaround (flutter/flutter#187686) 2026-06-09 41687333+rlueders@users.noreply.github.com [Impeller] Retry uncompressed when fixed-rate compression is exhausted (flutter/flutter#187586) 2026-06-09 burak.karahan@mail.ru Remove Material import from implicit animation tests (flutter/flutter#186673) 2026-06-09 engine-flutter-autoroll@skia.org Roll Packages from 13b49f4 to bd297cf (4 revisions) (flutter/flutter#187739) 2026-06-09 30870216+gaaclarke@users.noreply.github.com Updates dia_dll.py to support vs2026 (flutter/flutter#187714) 2026-06-09 bdero@google.com [Flutter GPU] Allow attaching specific texture mip levels and slices for rendering (flutter/flutter#187685) 2026-06-09 engine-flutter-autoroll@skia.org Roll Dart SDK from 39f1c44e294f to f3441f2067ae (1 revision) (flutter/flutter#187711) 2026-06-09 bdero@google.com [flutter_tools] Hot reload Flutter GPU shader bundles (flutter/flutter#187654) 2026-06-09 katelovett@google.com Update triage links (flutter/flutter#187709) 2026-06-09 engine-flutter-autoroll@skia.org Roll Skia from 43f135735152 to aeed11c35004 (11 revisions) (flutter/flutter#187721) 2026-06-09 jason-simmons@users.noreply.github.com Use workspace resolution for the meta package in dev/integration_tests/record_use_test_package (flutter/flutter#187733) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC louisehsu@google.com,stuartmorgan@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

flutter#187586) Fixes flutter#187564 ## Issue On the Pixel 10 (Tensor G5 / **Imagination PowerVR** GPU), Impeller's Vulkan backend crashes the raster thread under GPU pressure: ``` [ERROR:impeller/renderer/backend/vulkan/allocator_vk.cc] Unable to allocate Vulkan Image: ErrorCompressionExhaustedEXT Type: Texture2D ... Usage: { ShaderRead, RenderTarget } [ERROR:impeller/renderer/render_target.cc] Could not create color texture. [ERROR:impeller/renderer/render_target.cc] Render target does not have color attachment at index 0. F/libc: Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0 in tid NNNN (1.raster) ``` (In release builds the same failure surfaces as `[FATAL:flutter/impeller/display_list/canvas.cc(1471)] Check failed: back_texture. Context is valid:0` SIGABRT, or a bare SIGSEGV @ 0x20 on the `*.raster` thread.) ### Root cause Impeller requests **fixed-rate image compression** (`VkImageCompressionControlEXT`) for lossy render targets (`CreateOffscreenMSAA`'s color-resolve texture). When the PowerVR driver's fixed-rate-compression resources are exhausted, `vmaCreateImage` returns `VK_ERROR_COMPRESSION_EXHAUSTED_EXT`. `AllocatedTextureSourceVK` did not handle this — it logged and returned an invalid texture, which became a render target with no color attachment, and the raster thread then dereferenced the null texture. This is a regression: it does **not** reproduce on Flutter 3.41.9, but does on 3.44.x. It is PowerVR-specific (the error is tied to the driver's compression resource pool) and GPU-state-dependent (it fires once cumulative GPU compression pressure is high enough). ## Fix `VK_ERROR_COMPRESSION_EXHAUSTED_EXT` is, per the Vulkan spec, only returned for fixed-rate compression requests — so retrying the same allocation **without** compression is always a valid recovery. On that error, `AllocatedTextureSourceVK` now unlinks `VkImageCompressionControlEXT` from the create-info chain and retries `vmaCreateImage` once uncompressed (logging a one-time warning). The texture is identical, just stored uncompressed; the only cost is on the failure path (a small amount of extra memory/bandwidth for the affected texture, instead of a crash). ## Tests - **Unit test** (`allocator_vk_unittests.cc` → `RetriesUncompressedOnCompressionExhausted`): extends the Vulkan mock to advertise fixed-rate compression and to fail the first compressed `vkCreateImage` with `VK_ERROR_COMPRESSION_EXHAUSTED_EXT`, then asserts the allocator returns a **valid** texture and called `vkCreateImage` **twice** (compressed attempt + uncompressed retry). Passes; the other allocator tests are unaffected. - **On-device A/B** (Pixel 10, locally-built `android_profile_arm64`, same repro, same GPU-pressured state): | Engine | Result | |---|---| | Unpatched | `ErrorCompressionExhausted` → **SIGSEGV** on `1.raster` (crash) | | Patched | exhaustion → retry → **survives**; logs `Fixed-rate image compression exhausted; falling back to uncompressed image allocation` | ## Repro A pure-Flutter app that stacks enough full-screen `BackdropFilter` / `saveLayer` offscreen render targets to exhaust the PowerVR compression pool (see `lib/main.dart` in the linked repro). Crashes on the unpatched engine; runs on the patched one. Stable on either with `--no-enable-impeller`. ## Environment - Flutter 3.44.x (regressed from 3.41.9) - Device: Pixel 10, Android 17 (API 37) - GPU: Imagination PowerVR (Tensor G5); renderer Impeller / Vulkan ## Pre-launch checklist - [x] Added a unit test (or explained why not possible). - [x] Listed any breaking changes (none). - [x] Signed the [CLA](https://cla.developers.google.com/). --------- Co-authored-by: John "codefu" McDole <codefu@google.com>

github-actions Bot added engine flutter/engine related. See also e: labels. e: impeller Impeller rendering backend issues and features requests labels Jun 4, 2026

rlueders force-pushed the impeller-vulkan-compression-exhausted-retry branch from 65d411f to b37f7f7 Compare June 4, 2026 20:52

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[Impeller][Vulkan] Unhandled VK_ERROR_COMPRESSION_EXHAUSTED_EXT render-target allocation failure crashes the raster thread on PowerVR (Pixel 10) #187564

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Comment thread engine/src/flutter/impeller/renderer/backend/vulkan/test/mock_vulkan.cc Outdated

Comment thread engine/src/flutter/impeller/renderer/backend/vulkan/allocator_vk.cc Outdated

[Impeller] Address review: hoist compression check, drop auto deduction

619f621

- mock_vulkan: move compression_requested into the while condition - allocator_vk: use explicit types (vk::ImageCreateInfo::NativeType, vk::Result) instead of auto type deduction

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Stuck "Awaiting CICD label" check after modifying the description for a PR #186209

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Merge branch 'master' into impeller-vulkan-compression-exhausted-retry

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Roll Flutter from 66aaa9adb000 to c0a11291aa8c (17 revisions) flutter/packages#11881

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