Troubleshooting an infinite allocation error

Question

My application works fine for most inputs, but some input files make it allocate more and more memory at some point, until it is killed by the system's oom killer.

The application takes multiple hours to run, so babysitting it and manually interrupting it when its memory usage starts to break out is not an option.

I tried running the application with valgrind's massif, but since it gets killed by the system, it never produces an output file.

Is there an option to make massif write its snapshots to disk immediately?

Massif does seem to produce an output file for the application when interrupted by SIGINT, so this would probably work. Is there another tool that sends SIGINT to a process that consumes more than a certain amount of memory?