cannot set user id: Resource temporarily unavailable or Fork: Retry: Resource Temporarily Unavailable

Amjad reported this error while trying to login to the server:

cannot set user id: Resource temporarily unavailable

In the past he had reported this error:

Fork: Retry: Resource Temporarily Unavailable

This is due to the fact that the user has run out of free stacks.  In OEL 6.x , the stack setting is not done in /etc/security/limits.conf but in the file:

/etc/security/limits.d/90-nproc.conf

The default content in the file is:

cat /etc/security/limits.d/90-nproc.conf
# Default limit for number of user's processes to prevent
# accidental fork bombs.
# See rhbz #432903 for reasoning.

*          soft    nproc     1024
root       soft    nproc     unlimited

I changed this to:

After

$ cat /etc/security/limits.d/90-nproc.conf

# Default limit for number of user's processes to prevent

# accidental fork bombs.

# See rhbz #432903 for reasoning.

*          soft    nproc     16384

root       soft    nproc     unlimited

$

As soon as this change was made, Amjad was able to login.