Pre-Read

Recently I got so many messages about the signal 9 issue in android 12, it’s causing termux to crash whenever a user tries to run an application big enough to create ~15 child processes, and udroid, proot-distro are one of the most affected cause they make so many child processes when trying to any desktop environment.

[ UDROID ISSUES: #117, #123, #110 ]

So there is a new feature called PhantomService introduced in android 12 which looks for any user apps that has too many child process running and kills parent process of that app which leads to signal 9 in termux and full app crash in some apps.

Thankfully a fix is avalible to increase max_phantom_processes with adb commands but it requires PC, OTG or apps like ladb to execute and fix the issue.

in this blog post iam going fix this problem with termux by wireless debugging feature. so no pc, no any external app.

pre-requisites

  • A wifi connected android device with android 12+ version installed

  • Also termux-app with git installed

  • able to differentiate hostname and port number in a address

EX: in 10.0.0.29:8805 hostname is 10.0.0.29 and port number is 8805 they are seperated by a colon : ✌️

Steps

The easy way

Video coming soon

The dev way

we need to install adb in termux that supports pair feature. for some reason latest version of adb is not avalible in both termux and debian apt mirrors. luckly a guy on github called reddix did the hardwork of compiling adb with gigs of android source code. to install them use

git clone https://github.com/rendiix/termux-adb-fastboot
cd termux-adb-fastboot
cp -v binary/$(getprop ro.product.cpu.abi)/bin/* ~/../usr/bin/

then navigate to settings>developer option and enable Wireless Debugging.

if you connected to a wifi you will promted with a dialog to asking permission to allow debugging in wireless network. Allow it

Now open your termux and settings in a split screen

make sure you can see debug IP address, IP address, and passcode. ( resize it )

image showing where to see for ports

back in termux we need to pair with the debugging service

adb pair localhost:<connection port> <PassCode>

Now connect to the device with

adb connect localhost:<debug port>

if no errors appeared then successfully connected to the device. you can check your device connection by adb devices

try repeating previous steps if something happens to work. Settings may turn off wireless debugging sometimes after the first pairing.

Finally fix phantom issue with this command

adb \
    shell \
    device_config \
    put activity_manager \
    max_phantom_processes 214181594

adb shell device_config \
    set_sync_disabled_for_tests persistent

the above command increases max phantom processes and makes sure it cant be changed android at boot

🎉 Now you can use termux proot in android 12

Side Effects

Increasing phantom process limit causes more process-heavy apps other than termux to run in the background which could cause performance issues when dealing with games or heavy daily drive usage in mid-range phones.

when you feel the stutter and want to make things back to normal use this command.

adb shell device_config \
    set_sync_disabled_for_tests none

Externel

SaicharanKandukuri/termux-android12-phantom-fix : (scripts to fix issue with termux in android 12)

RandomCoderOrg/ubuntu-on-android (Run Ubuntu with pre-installed Desktop Environments in android/termux with ease! Everything is preinstalled so just download install and done🚀🚀)

[ UDROID ISSUES: #117, #123, #110 ]