Re: `pg_ctl init` crashes when run concurrently; semget(2) suspected

> On Aug 12, 2025, at 4:07 PM, Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
>
> On Mon, Aug 11, 2025 at 10:56 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> A bit more research later: OpenBSD behaves like NetBSD, while
>> FreeBSD behaves like Linux. So that's pretty inconclusive about
>> what the aboriginal behavior was. I also found that OpenIndiana
>> behaves like Linux.
>
> Out of curiosity, FreeBSD changed that in 2016:
>
> https://github.com/freebsd/freebsd-src/commit/f00fb5457ebf5907055e420d803ac67fb098109e

I believe that this is the code in macOS's "XNU" [1][2] which has similar
logic (unsurprisingly) to the FreeBSD code before the identified commit [3].

best.

-greg

[1] https://github.com/apple-oss-distributions/xnu/blob/e3723e1f17661b24996789d8afc084c0c3303b26/bsd/kern/sysv_sem.c#L860-L889
[2] "XNU is a hybrid kernel combining the Mach kernel developed at Carnegie Mellon University with components from FreeBSD and a C++ API for writing drivers called IOKit."
[3] https://github.com/freebsd/freebsd-src/commit/f00fb5457ebf5907055e420d803ac67fb098109e