Re: Weird failure with latches in curculio on v15

Hi,

On 2023-02-01 10:53:17 +0900, Michael Paquier wrote:
> While browsing the buildfarm, I have noticed this failure on curcilio:
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=curculio&dt=2023-02-01%2001%3A05%3A17
>
> The test that has reported a failure is the check on the archive
> module callback:
> # Failed test 'check shutdown callback of shell archive module'
> # at t/020_archive_status.pl line 248.
> # Looks like you failed 1 test of 17.
> [02:28:06] t/020_archive_status.pl ..............
> Dubious, test returned 1 (wstat 256, 0x100)
> Failed 1/17 subtests
>
> Looking closer, this is a result of an assertion failure in the latch
> code:
> 2023-02-01 02:28:05.615 CET [6961:8] LOG: received fast shutdown request
> 2023-02-01 02:28:05.615 CET [6961:9] LOG: aborting any active transactions
> 2023-02-01 02:28:05.616 CET [30681:9] LOG: process 30681 releasing ProcSignal slot 33, but it contains 0
> TRAP: FailedAssertion("latch->owner_pid == MyProcPid", File: "latch.c", Line: 451, PID: 30681)

Given the ProcSignal LOG message before it, I don't think this is about
latches.

> The information available in standby2.log shows that 30681 is the
> startup process. I am not sure what all that means, yet.
>
> Thoughts or comments welcome.

Perhaps a wild write overwriting shared memory state?

Greetings,

Andres Freund