Hello,

> Did anyone test this fix for case of fork() being called from Python sub interpreter?
>

Not specifically, unless it's part of the test suite.
Anyway, unless this problem is systematic - which I doubt - it
probably wouldn't have helped.

> Getting a report of fork() failing in sub interpreters under mod_wsgi that may be caused by this change. Still investigating.
>
> Specifically throwing up error:
>
>  Couldn't create autoTLSkey mapping
>

Hmmm.
If you can, try strace or instrument the code (perror() should be
enough) to see why it's failing.
pthread_setspecific() can fail with:
- EINVAL, if the TLS key is invalid (which would be strange since we
call pthread_key_delete()/pthread_key_create() just before)
- or ENOMEM, if you run out of memory/address space

The later seems much more likely (e.g. if many child processes and
subinterpreters are created).
BTW, if this is a bug report from someone else, tell him to post here,
it'll be easier.
And we don't byte :-)