adb shell operation not permitted

Question

I try to run

adb shell kill 5539

where 5539 is a process id found when running adb shell ps, but I get

/system/bin/sh: kill: 5539: Operation not permitted

How can I rectify my permissions?

This is the only adb documentation on kill:

kill [options]

Kill all processes associated with (the app's package name). This command kills only processes that are safe to kill and that will not impact the user experience. Options are:

--user | all | current: Specify user whose processes to kill; all users if not specified.

Answer 1

My methods:

Without root

adb shell am force-stop <package name>

I don't know how to do it with PID, kill <PID> and kill -9 <PID> don't work in my case

With root

I have also installed BusyBox to get more UNIX tools on my device

adb shell "su -c 'kill $(pidof <package name>)'"

or

adb shell "su -c 'kill <PID>'"

Answer 2

You need to restart adb as root

This will give you permissions to kill the process.

$ adb root

$ adb shell kill 5539