[Impeller][Android][GLES] FragmentProgram causes SIGABRT on second app launch — "Must be able to encode GL commands without error" #186186

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1. mbcorona

   added

   c: crashStack traces logged to the consoleStack traces logged to the console

   platform-androidAndroid applications specificallyAndroid applications specifically

   engineflutter/engine related. See also e: labels.flutter/engine related. See also e: labels.

   e: impellerImpeller rendering backend issues and features requestsImpeller rendering backend issues and features requests

   team-engineOwned by Engine teamOwned by Engine team

   workaround availableThere is a workaround available to overcome the issueThere is a workaround available to overcome the issue

   fyi-androidFor the attention of Android platform teamFor the attention of Android platform team

   and removed

   c: crashStack traces logged to the consoleStack traces logged to the console

   on May 7, 2026
2. mbcorona commented on May 7, 2026

   

   mbcorona

   on May 7, 2026

   Member

   More actions

   Hi @heyi1994 thanks for the detailed report and providing the root cause analysis, I am routing to the engine for further investigation.
3. jason-simmons commented on May 8, 2026

   

   jason-simmons

   on May 8, 2026

   Contributor

   More actions

   Tried running some apps that use FragmentProgram.fromAsset with Impeller/GLES but was unable to reproduce this.

   Do you have a simple app that reproduces it? And does it only happen on specific devices?

   The Impeller Vulkan back end writes a pipeline cache to disk (see https://github.com/flutter/flutter/blob/master/engine/src/flutter/impeller/renderer/backend/vulkan/pipeline_cache_data_vk.cc). But the GLES back end is not doing that.
4. heyi1994 commented on May 9, 2026

   

   heyi1994

   on May 9, 2026

   Last edited by heyi1994

   Author

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   Update: Root cause identified via bisection

   After extensive bisection on the affected device (OPPO CPH2203, PowerVR Rogue
   GM9446, Android 13), the crash has been reduced to a minimal reproducer
   and the root cause identified.

   Minimal reproducer

   The crash requires only a trivial shader (simple.frag) with no uniforms —
   shader complexity is not the factor. The only condition that triggers the
   crash is having two widgets that each call FragmentProgram.fromAsset()
   with the same asset path, running simultaneously:

   #include <flutter/runtime_effect.glsl>
    out vec4 fragColor;
   
    void main() {
       fragColor = vec4(0.0,0.0,0.0,1.0);
   }
   

   import 'dart:ui' as ui;
   import 'package:flutter/material.dart';
   
   void main() => runApp(
   const MaterialApp(
     home: Scaffold(
       body: Column(
         children: [
           ShaderWidget(path: 'shaders/simple.frag'),
           ShaderWidget(path: 'shaders/simple.frag'),
         ],
       ),
     ),
   ),
   );
   
   class ShaderWidget extends StatefulWidget {
   final String path;
   
   const ShaderWidget({super.key, required this.path});
   
   @override
   State<ShaderWidget> createState() => _ShaderWidgetState();
   }
   
   class _ShaderWidgetState extends State<ShaderWidget>
     with SingleTickerProviderStateMixin {
   ui.FragmentShader? _shader;
   
   @override
   void initState() {
     super.initState();
     _loadShader();
   }
   
   Future<void> _loadShader() async {
     final program = await ui.FragmentProgram.fromAsset(widget.path);
     if (!mounted) return;
     setState(() => _shader = program.fragmentShader());
   }
   
   @override
   void dispose() {
     _shader?.dispose();
     super.dispose();
   }
   
   @override
   Widget build(BuildContext context) {
     if (_shader == null) return const SizedBox(width: 200, height: 100);
     return CustomPaint(
       painter: _SimplePainter(_shader!),
       child: const SizedBox(width: 200, height: 100),
     );
   }
   }
   
   class _SimplePainter extends CustomPainter {
   final ui.FragmentShader shader;
   
   const _SimplePainter(this.shader);
   
   @override
   void paint(Canvas canvas, Size size) =>
       canvas.drawRect(Offset.zero & size, Paint()..shader = shader);
   
   @override
   bool shouldRepaint(_SimplePainter old) => false;
   }
                      

   Bisection results (force-stop → relaunch methodology)

   Configuration	Crashes?
   1× simple.frag	No
   2× simple.frag (same path)	Yes
   2× separate files (identical content, different paths)	No
   1× complex shader (48 uniforms)	No
   2× complex shader (same path)	Yes
   complex shader + copy at different path	No

   Root cause

   FragmentProgram.fromAsset() has a static cache keyed by asset path. Two
   widgets calling it with the same path receive the same FragmentProgram
   instance. Both then call program.fragmentShader(), producing two
   FragmentShader objects that share the same underlying GL program ID in
   Impeller GLES.

   On first launch the GL program is compiled fresh — no crash. On the second
   launch (after force-stop), the PowerVR driver restores the program from its
   GL_IMG_program_binary disk cache. When Impeller submits two draw calls
   in the same frame both using the same cached GL program ID, the PowerVR driver
   crashes with a use-after-free (SIGSEGV, fault addr 0x000192010300b821,
   x20=0x220192010300b801) or FML_CHECK(result) failure in
   render_pass_gles.cc:692.

   Clearing app data resolves the crash until the next force-stop cycle, because
   it clears the driver-level binary cache.

   Workaround

   Use a different file path for each concurrent widget instance (even with
   identical content). This gives each widget an independent GL program ID.

   Suggested fix

   • Blacklist GL_IMG_program_binary on PowerVR in Impeller GLES (similar to
     the existing IsKnownBadDriver() mechanism), or
   • Ensure each fragmentShader() call produces an independent GL program
     object rather than sharing one across all FragmentShader instances from the
     same FragmentProgram

   Device info:

   • Device: OPPO CPH2203
   • Build:
     OPPO/CPH2203/OP4F43L1:13/TP1A.220905.001/R.206769c-2:user/release-keys
   • Android: 13 / ABI: arm64
   • GPU: Imagination Technologies, PowerVR Rogue GM9446
   • OpenGL ES: 3.2 (build 1.13@5776728) — ro.opengles.version: 196610
5. gaaclarke

   added

   P2Important issues not at the top of the work listImportant issues not at the top of the work list

   triaged-engineTriaged by Engine teamTriaged by Engine team

   on May 11, 2026
6. gmackall

   added

   triaged-androidTriaged by Android platform teamTriaged by Android platform team

   on May 19, 2026
7. flutter-triage-bot

   removed

   fyi-androidFor the attention of Android platform teamFor the attention of Android platform team

   triaged-androidTriaged by Android platform teamTriaged by Android platform team

   on May 19, 2026