Reserved Process ID

Question

As per my knowledge Process ID 1 is reserved for init.

What does process id 2 indicate? why no softlink to the binary executable for this process ID.

sudo ls -l /proc/1/exe    
lrwxrwxrwx 1 root root 0 Apr 24 14:53 /proc/1/exe --> /sbin/init

But for /proc/2/exe

ls : cannot read symbolic link /proc/2/exe: No such file or directory
lrwxrwxrwx 1 root root 0 Apr 24 14:53 /proc/2/exe

Im using Ubuntu 12.04.

pls share your knowledge.

score 1 · Answer 1 · answered Apr 26 '13 at 12:03

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It's because there is no binary to link to. This process was probably started by the kernel itself. Take a look at the out put of ps aux. Any process you see listed in brackets will not have a exe soft link either.

answered Apr 26 '13 at 12:03

gogators

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score 0 · Accepted Answer · edited May 23 '17 at 12:04

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because at the moment you are asking there is no process of pid 2. the kernel allocates pids at will.

Or because pid 2 is for some kernel task; on my machine it is for kthreadd which is some pure kernel process. See this answer.

edited May 23 '17 at 12:04

Community

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answered Apr 26 '13 at 11:10

Basile Starynkevitch

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so whenever a process dies, corresponding folder also deleted in /proc right. But folder /proc/2 is available. – Jeyaram Apr 26 '13 at 11:11
process of pid 2 could be a system process, not belonging to you. then `/proc/2/` exists but is not accessible *by you* – Basile Starynkevitch Apr 26 '13 at 11:27
I guess, process 2 couble forked by process 1, so there is no binary exe link in that /proc/2/exe. – Jeyaram Apr 26 '13 at 11:33

Reserved Process ID

2 Answers2