Horton

Re: valgrind error

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2020-06-06T03:03:24Z
Lists: pgsql-hackers 
Noah Misch <noah@leadboat.com> writes:
> On Fri, Jun 05, 2020 at 12:17:54PM -0400, Tom Lane wrote:
>> as you have it, I'd prefer to use
>> -       fun:pg_comp_crc32c
>> +       fun:pg_comp_crc32c_sb8
>> which precisely matches what 4f700bc did.  The other way seems like
>> it's giving a free pass to problems that could lurk in unrelated CRC
>> implementations.

> The undefined data is in the CRC input, namely the padding bytes in xl_*
> structs.

Oh, I see.  Objection withdrawn.

> Apparently, valgrind-3.15.0 doesn't complain about undefined input
> to _mm_crc32_u* functions.  We should not be surprised if Valgrind gains the
> features necessary to complain about the other implementations.

Perhaps it already has ... I wonder if anyone's tried this on ARMv8
lately.

			regards, tom lane

Commits

  1. Refresh function name in CRC-associated Valgrind suppressions.

  2. Reorganize our CRC source files again.