Horton

Re: Clang UndefinedBehaviorSanitize (Postgres14) Detected undefined-behavior

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Ranier Vilela <ranier.vf@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-08-28T02:42:08Z
Lists: pgsql-hackers 
On Thu, Aug 27, 2020 at 12:57:20PM -0400, Alvaro Herrera wrote:
> On 2020-Aug-27, Ranier Vilela wrote:
> > indexcmds.c (1162):
> > memcpy(part_oids, partdesc->oids, sizeof(Oid) * nparts);
> 
> Looks legit, and at least per commit 13bba02271dc we do fix such things,
> even if it's useless in practice.
> 
> Given that no buildfarm member has ever complained, this exercise seems
> pretty pointless.

Later decision to stop changing such code:
https://postgr.es/m/flat/e1a26ece-7057-a234-d87e-4ce1cdc9eaa0@2ndquadrant.com

Commits

  1. Avoid memcpy() with a NULL source pointer and count == 0

  2. Avoid calling memcpy() with a NULL source pointer and count == 0.