Horton

Re: Clang UndefinedBehaviorSanitize (Postgres14) Detected undefined-behavior

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Noah Misch <noah@leadboat.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@2ndquadrant.com>, Ranier Vilela <ranier.vf@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-08-28T16:54:42Z
Lists: pgsql-hackers 
On Thu, Aug 27, 2020 at 11:04 PM Noah Misch <noah@leadboat.com> wrote:
> On Thu, Aug 27, 2020 at 11:11:47PM -0400, Tom Lane wrote:
> > It's surely not hard to visualize cases where necessary code could
> > be optimized away if the compiler thinks it's entitled to assume
> > such things.
>
> Good point.

I wonder if we should start using -fno-delete-null-pointer-checks:

https://lkml.org/lkml/2018/4/4/601

This may not be strictly relevant to the discussion, but I was
reminded of it just now and thought I'd mention it.

-- 
Peter Geoghegan

Commits

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

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