Horton

Re: Worth using personality(ADDR_NO_RANDOMIZE) for EXEC_BACKEND on linux?

Nathan Bossart <bossartn@amazon.com>

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From: "Bossart, Nathan" <bossartn@amazon.com>
To: Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL Development <pgsql-hackers@postgresql.org>
Date: 2022-01-07T20:20:31Z
Lists: pgsql-hackers 
On 11/23/21, 11:29 AM, "Thomas Munro" <thomas.munro@gmail.com> wrote:
> Here's a patch for Linux and also FreeBSD.  The latter OS decided to
> turn on ASLR by default recently, causing my workstation to fail like
> this quite reliably, which reminded me to follow up with this.  It
> disables ASLR in pg_ctl and pg_regress, which is enough for check and
> check-world, but doesn't help you if you run the server directly
> (unlike the different hack done for macOS).
>
> For whatever random reason the failures are rarer on Linux (could be
> my imagination, but I think they might be clustered, I didn't look
> into the recipe for the randomness), but even without reproducing a
> failure it's clear to see using pmap that this has the right effect.
> I didn't bother with a check for the existence of ADDR_NO_RANDOMIZE
> because it's since 2.6.12 which is definitely ancient enough.

FWIW I just found this patch very useful for testing some EXEC_BACKEND
stuff on Linux.

Nathan

Commits

  1. Make EXEC_BACKEND more convenient on Linux and FreeBSD.

  2. Make EXEC_BACKEND more convenient on macOS.