Which tests, and against which PoCs? The public php2shell kits already crash workers on stock 8.4 (8/8 crash, 0/8 shell) — so "turned into DoS" may be the status quo, not your result.
And firing the OOM is memory_limit working as designed, not exploiting a system.
And firing the OOM is memory_limit working as designed, not exploiting a system.
Pix, or GTFO.