Can't mount devpts on /newroot/dev/pts: Too many open files

[furunkel]

Hi,
I'm using bubblewrap to run several hundreds of thousands of untrusted programming contest submissions.
However, after some time I get Can't mount devpts on /newroot/dev/pts: Too many open files, and sometimes bwrap: Can't mount proc on /newroot/proc: Too many open files.
Strangely, after restarting the process, the error appears much sooner (after a few hundreds of bwrap invocations).
I tried to increase the corresponding operating system limit but that does not seem to be the problem.
Does anybody have an idea what the problem might be?

[rusty-snake]

mount(2):

EMFILE (In case no block device is required:) Table of dummy devices is full.

---

I tried to increase the corresponding operating system limit

How? Which limit?

[furunkel]

Thanks! I did look into the man page, but somehow overlooked this.
The limit I was referring to was the usual "number of open files" limit, so indeed not related to this.
Do you know of any way to work around this? Are there missing umount calls in bubblewrap or is this an OS limitation?