Okay, that nailed it down - the problem is the number of open file descriptors is exceeding your system limit. I suspect the connection to the Mellanox drivers is solely due to it also having some descriptors open, and you are just close enough to the boundary that it causes you to hit it.
See what you get with "ulimit -a" - you are looking for a line that indicates "open files", meaning the max number of open file descriptors you are allowed to have. You can also check the system imits with "cat /proc/sys/fs/file-max" (might differ with flavor of Linux you are using). There are a number of solutions - here is an article that explains them: https://www.linuxtechi.com/set-ulimit-file-descriptors-limit-linux-servers/ Ralph
