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From: "paul.groke at dynatrace dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/54185] [4.7/4.8 Regression] condition_variable not
 properly destructed
Date: Wed, 21 Sep 2022 18:30:06 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D54185

Paul Groke <paul.groke at dynatrace dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |paul.groke at dynatrace do=
t com

--- Comment #16 from Paul Groke <paul.groke at dynatrace dot com> ---
(In reply to  Jonathan Wakely)

> It fails reliably on AIX too.

I think that is because of non-conformant behavior of AIX's
pthread_mutex_destroy. It will return EBUSY as long as there are still thre=
ads
executing a wait function, even if they're already blocked on re-acquiring =
the
mutex. If you ignore the error and simply releases/unmap the memory of the =
CV,
you have a good chance of getting a SIGSEGV in the wait function later (aft=
er
it has re-acquired the mutex and presumably proceeds to mark the CV
"non-busy").

In our tests, we get the EBUSY every time if we delete the CV while holding=
 the
mutex on the same thread. The SIGSEGV also reproduces quite well, although =
for
some reason only with 32 bit builds. (AIX 7.1, oslevel 7100-05-03-1837)=