Troubleshooting system-level problems

Runaway processes

A ``runaway process'' is a process that enters an infinite loop and spawns new processes. This can cause an overflow in the proc table that causes other processes to fail with the No more processes: error message.

A runaway process can cause an error that locks up the keyboard, preventing anything that the user types from reaching the system. Because of this, a runaway process cannot be stopped from the invoking terminal.

To continue, you must identify and stop the runaway process:

  1. Log in as root on a terminal (or console screen) that is not locked.

  2. Enter the ps -ef command and press <Enter>. The system displays full information on all the current processes and their process identification numbers (PIDs). Find the PID of the runaway program. You may see a program that is consuming more CPU time than is reasonable, or may find a large number of processes with a common parent who are running the same program.

  3. Enter the kill PID command. The program should stop in a few seconds. If the process does not stop, enter the kill -9 PID command.
The last command may leave temporary files that are usually removed when a program terminates normally, or a non-echoing terminal. Refer to ``Restoring non-echoing terminals'' to restore the terminal to normal operation.

If the runaway process does not stop when you enter kill with the -9 option, the process is considered ``unkillable''. If the unkillable process is a user's shell, you must stop the process before that user can continue working. To stop an unkillable process, you must reboot the system. Use the following procedure:

  1. Log in as root and send a message using wall(ADM) to the other system users notifying them of the impending shutdown.

  2. When all the users have logged out, shut down the system by entering init 6. The root prompt (#) is returned, but the shutdown process begins soon afterward.

  3. Reboot the system by pressing <Enter> at the Boot: prompt.
The unkillable process no longer appears when you run ps.
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SCO OpenServer Release 5.0.7 -- 11 February 2003