Fixing Termux Error Process Completed (Signal 9) on Android

Many Termux users on Android encounter the “process completed (signal 9)” error, particularly on Android 12 and later versions. This error can be quite perplexing, especially for those relying on Termux for advanced operations. This comprehensive guide aims to demystify and provide solutions to this error.

Understanding the Error

What is the “Signal 9” Error in Termux?

The “process completed (signal 9)” error in Termux primarily occurs due to Android 12’s added mechanism of monitoring and killing forked child processes started by apps like Termux. If an app spawns more than 32 processes, Android automatically terminates them. This change has significantly impacted apps that require multiple processes, like Termux.

Why Does This Error Occur?

• Android’s Process Limitations: Android 12 monitors the number of child processes spawned by an app, limiting them to a default of 32. Exceeding this count leads to automatic termination of processes, resulting in the error.
• Inconsistency Across Android Skins: Different OEMs (like Xiaomi, Samsung) might not have incorporated Google’s changes in their Android skins, leading to variations in how this error is handled across devices.

Resolving the Error

Method 1: Disabling the Phantom Process Killer (Stock Android 12L and Beyond)

1. Enable Developer Options: Navigate to ‘Settings’ > ‘About Phone’ and find the ‘Build Number’. Tap on it multiple times to enable Developer Options.
2. Access Developer Options: Go to ‘Settings’ > ‘System’ > ‘Developer Options’.
3. Disable Phantom Process Killer: In the Developer Options, find the ‘Feature Flags’ section and look for the toggle to turn off ‘settings_enable_monitor_phantom_procs’.

Method 2: Using Android Debug Bridge (ADB) for Non-Stock Android

1. Install ADB: Ensure Android Debug Bridge (ADB) is installed on your computer. You can follow guides on XDA Developers to install ADB on Windows, macOS, or Linux.
2. Connect Device via ADB: After installation, confirm your device is connected using the adb devices command.
3. Run ADB Commands: Execute the following ADB shell commands:
   • adb shell "/system/bin/device_config set_sync_disabled_for_tests persistent"
   • adb shell "/system/bin/device_config put activity_manager max_phantom_processes 2147483647"
   • adb shell settings put global settings_enable_monitor_phantom_procs false

Conclusion

The “process completed (signal 9)” error in Termux on Android 12 and later versions stems from the OS’s process monitoring mechanism. By following the above methods, users can effectively resolve this error. It’s important to adapt the solution based on your Android version and skin. Regularly updating Termux and staying informed about changes in Android’s operation can also help in preemptively avoiding such issues.