Error after upgrading Flutter version from 2.1 to 3.27

error.md

Application crashes after unlocking the phone – "failed to attach to thread: Permission denied"

After upgrading my Flutter application from version 2.1 to 3.27, some errors appeared. I managed to resolve all null safety-related issues, but one critical error remains.

Issue

When I lock and then unlock the smartphone while the app is running, the application crashes, and I see the following messages in the terminal:

I/mx.fleetmonito(30053): Thread[6,tid=30064,WaitingInMainSignalCatcherLoop,Thread*=0xb4000071103b4be0,peer=0x131426a8,"Signal Catcher"]: reacting to signal 3  

I/mx.fleetmonito(30053): Wrote stack traces to tombstoned  

F/crash_dump64(31601): crash_dump.cpp:474] failed to attach to thread 813: Permission denied  

No error appears in Sentry.

What I’ve Tried

• Verified that all dependencies are updated.
• Reviewed Android permissions in AndroidManifest.xml.
• Checked for any breaking changes in Flutter between versions 2.1 and 3.27.
• Debugged using logcat, but the messages don’t give clear clues about the root cause.

Questions

1. What could be causing this crash when unlocking the phone?
2. Are there any Flutter or Android changes between versions that could explain this behavior?
3. How can I get more detailed logs to diagnose this issue further?

Environment:

• Flutter version: (insert exact version)
• Android version: (insert affected version)
• Device/Emulator: (specify if it happens on all devices or only some)

Any insights or suggestions would be greatly appreciated!