This happens with many different programs from the terminal. Usually accompanied with some error message about not being able to allocate memory.
When I try "free -m" this is the output:
martin@martin-ThinkPad-T410:~$ free -m total used free shared buffers cached
Mem: 3823 3079 744 0 99 1159
-/+ buffers/cache: 1820 2003
Swap: 3953 60 3893Why is my swap usage so low? Is this related?
12 Answers
You must have set a limit for the maximum number of processes in /etc/security/limits.conf or perhaps some default is set in Ubuntu.
I had that set to 350 processes to prevent accidential fork-bombs. What drove me crazy - when my processes couldn't fork anymore, the number of processes I ran at the time was far from the limit.
Turns out the reason for that was, that not processes were counted, but kernel level threads.
ps -efL | grep ^$USER | wc -l indeed showed that I was close to the limit. The many tabs/windows I had open in chromium alone could amount to over 100 such threads - no wonder I hit that limit easily.
The problem ended up being this one:
fuser process started by cron job forking uncontrollably
