Horton

Re: pg_verify_checksums and -fno-strict-aliasing

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

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Magnus Hagander <magnus@hagander.net>
Cc: Fabien COELHO <coelho@cri.ensmp.fr>, Michael Banck <michael.banck@credativ.de>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-08-30T21:49:04Z
Lists: pgsql-hackers 
Magnus Hagander <magnus@hagander.net> writes:
> On Thu, Aug 30, 2018 at 4:39 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> (The right fix, of course, is to malloc the work buffer rather than
>> put it on the stack.)

> So if I get you  right, you're saying the attached patch should be all
> that's needed?

Well, that's some of what's needed.  I notice this code is also being
sloppy about whether block numbers are signed or unsigned, which means
it'd probably misbehave on relations exceeding 2^31 blocks.  I have
a patch in progress to clean all that up, though I'm still working
on the strict-aliasing part.

			regards, tom lane

Commits

  1. Avoid using potentially-under-aligned page buffers.

  2. Code review for pg_verify_checksums.c.

  3. Make checksum_impl.h safe to compile with -fstrict-aliasing.