quoted

Cannot call memory_failure() directly from the fault handler because
mmap_lock (and others) are held.

Could you please explain which lock makes it unfeasible to call memory_failure() directly and
why? I'm somewhat confused. But I agree using memory_failure_queue() should be a good idea.

I tried calling memory_failure() directly, and my system just hung. I made the assumption
that it had deadlocked based somewhat on the comments in mm/memory.c about mmap_lock
being held ... but I didn't dig into what had gone wrong.

-Tony