Re: lib/54661: pthread_self() returns invalid value in some circumstances

[Tom Lane <tgl%sss.pgh.pa.us@localhost>]

The following reply was made to PR lib/54661; it has been noted by GNATS.

From: Tom Lane <tgl%sss.pgh.pa.us@localhost>
To: gnats-bugs%netbsd.org@localhost, Joerg Sonnenberger <joerg%bec.de@localhost>
Cc: lib-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: lib/54661: pthread_self() returns invalid value in some circumstances
Date: Wed, 30 Oct 2019 11:05:05 -0400

 Joerg Sonnenberger <joerg%bec.de@localhost> writes:
 >  We didn't allow dynamic loading of libpthread at all for a long time. I
 >  still believe allowing it was a mistake, but *shrug*. We certainly do
 >  not support calling pthread_create if libpthread was not initially
 >  loaded. As much pthread_self() can only ever return the main thread.
 
 Hmm.  So the idea is to lock down libpthread.so to act like the stub
 functions, if it's dlopen'd after main() initialization?  Weird, but
 no skin off my nose --- from a Postgres-centric viewpoint, we don't
 support anybody trying to start additional threads inside a Python
 function, anyway.
 
 In that case we should close this as not-a-bug, and I'll go rant
 at the Python people that they shouldn't be making an error check
 on pthread_self's result.  Or at least, -1 is a really unfortunate
 choice of value for PYTHREAD_INVALID_THREAD_ID.
 
 			regards, tom lane