Use a core dump: good idea!
haypo> Using my fuzzer (Fusil) on Python trunk, I got sometimes
haypo> errors on multiprocessing.Pool():
haypo>
haypo> Fatal Python error: PyEval_AcquireThread: NULL new thread state
I read the source code of the thread module. This error means that
PyThreadState_New() returns NULL which occurs if malloc() failed. I hit this
error using my fuzzer because the fuzzer limits the total memory to something
around 100 MB using setrlimit().
Said differently: in low memory condition, creating a new thread may exit the
whole Python process if a memory allocation fail.
--
Sometimes, I get another error, similar to the "NULL new thread state" error:
Fatal Python error: Couldn't create autoTLSkey mapping
I guess that the reason is the same: memory allocation failed. It should be
the malloc() in find_key() (Python/thread.c).