[STDERR] lscgid: execve():/usr/local/lsws/lsphp73/bin/lsphp: Resource temporarily unavailable

Hello guys,

I'm kinda lost here. I have a lot of servers using the same configuration and working fine, but one specific server is returning this error with ANY php file, even a simple phpinfo:

[STDERR] lscgid: execve():/usr/local/lsws/lsphp73/bin/lsphp: Resource temporarily unavailable

From what I was able to debug, this only happens when file ownership is set to www-data:www-data (or root:www-data), and the following PHP extapp is setted:
extUser www-data # (or root)
extGroup www-data

If I set to another user, it runs just fine.

I guess I'm hitting some limit in Linux with this user, but I'm not sure which one.

www-data@xxxxxxx:~$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 257607
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1048576
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 500000
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited
Does anyone have any idea what should I try next?

Okay, so I guess I was right. I'm hitting some kind of weird limit.

Turns out I'm also running nginx with "worker_processes auto" in a server with 16 cores. It seems nginx is allocating everything possible to its process, and I can't run OLS or LSPHP using the same user.

I limited nginx worker_process to 4, and immediately LSPHP started responding again!

Now, which limit was I hitting? I have no idea.