Horton

Re: Non-robustness in pmsignal.c

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2022-10-08T00:49:18Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2022-10-07 20:35:58 -0400, Tom Lane wrote:
>> Andres Freund <andres@anarazel.de> writes:
>>> Why are we even tracking PM_CHILD_UNUSED / PM_CHILD_ASSIGNED in shared memory?

>> Because those flags are set by the child processes too, cf
>> MarkPostmasterChildActive and MarkPostmasterChildInactive.

> Only PM_CHILD_ACTIVE and PM_CHILD_WALSENDER though. We could afford another
> MaxLivePostmasterChildren() sized array...

Oh, I see what you mean --- one private and one public array.
Maybe that makes more sense than what I did, not sure.

>> I am, but I'm not inclined to push this immediately before a wrap.

> +1

OK, I'll take a little more time on this and maybe code it up as
you suggest.

			regards, tom lane

Commits

  1. Harden pmsignal.c against clobbered shared memory.