You probably came to this page because you saw some processes like kidle_inject/0, kidle_inject/1 running in your Linux or Ubuntu system. This probably happened just after your system had experienced an extremely high load. The overloading of your CPU may have been due to some buggy website or webpage you visited in your browser. Or it may be due to some code in your script that caused an infinite loop to run.
So what is this kidle_inject process? It is a process that is automatically created by your system. When? When it finds out that your CPU has been overloaded so much that it is not finding enough idle time to keep it cool! In other words, when your CPU is overheating.
So a kidle_inject is a special kernel thread created for each processor in your system. They will be like kidle_inject/0 for first processor, kidle_inject/1 for second processor and so on. kidle_inject is a real time high priority process and hence will force your CPU to spend some time in idle without doing any work. This will prevent it from overheating.
Please note that these are system processes launched in response to another application that is causing system overload. They are spawned to throttle your processors to prevent overheating and melting down of your CPU.
So if you find these kidle_inject processes, DO NOT kill them. Instead find out which appilcation or process of yours is overloading the CPU and STOP THAT culprit application. Once you do that, all these kidle_inject/N processes will go away automatically.