Re: Postmaster self-deadlock due to PLT linkage resolution - Mailing list pgsql-hackers

From Thomas Munro
Subject Re: Postmaster self-deadlock due to PLT linkage resolution
Date
Msg-id CA+hUKGLJ7AFD0iqkM096rkJRxdTZXCWD-naew7yG1UUSraUmhA@mail.gmail.com
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In response to Re: Postmaster self-deadlock due to PLT linkage resolution  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Postmaster self-deadlock due to PLT linkage resolution
List pgsql-hackers
On Wed, Aug 31, 2022 at 12:26 AM Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Aug 30, 2022 at 8:17 AM Thomas Munro <thomas.munro@gmail.com> wrote:
> > FWIW I suspect FreeBSD can't break like this in a program linked with
> > libthr, because it has a scheme for deferring signals while the
> > runtime linker holds locks.  _rtld_bind calls _thr_rtld_rlock_acquire,
> > which uses the THR_CRITICAL_ENTER mechanism to cause thr_sighandler to
> > defer until release.  For a non-thread program, I'm not entirely sure,
> > but I don't think the fork() problem exists there.  (Could be wrong,
> > based on a quick look.)
>
> Well that seems a bit ironic, considering that Tom has worried in the
> past that linking with threading libraries would break stuff.

Hah.  To clarify, non-thread builds don't have that exact fork()
problem, but it turns out they do have a related state clobbering
problem elsewhere, which I've reported.



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