From: Andres Freund <andres@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Gurjeet Singh <gurjeet@singh.im>
Cc: Peter Eisentraut <peter_e@gmx.net>
Cc: PGSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels
Date: Tue, 10 Jun 2014 17:24:19 +0200
Message-ID: <20140610152419.GL8406@alap3.anarazel.de> (raw)
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On 2014-06-10 11:14:43 -0400, Tom Lane wrote:
> Sure, but what's that have to do with this? Any Red Hat or PGDG RPM will
> come with this code already enabled in the build, so there is no need for
> anyone to have a GUC to play around with the behavior.
That's imo a fair point. Unless I misunderstand things Gurjeet picked
the topic up again because he wants to increase the priority of the
children. Is that correct Gurjeet?
I do think a GUC might be a nicer interface for this than a
#define. Possibly even with a absolute reset value for the children. But
only because there's no way, afaics, to explicitly reset to the default
value.
> >> I remain of the opinion that allowing nonprivileged people to decide
> >> whether that code is active or not is unsafe from a system level.
>
> > On what factual basis?
>
> Because it would convert the intended behavior (postmaster and only
> postmaster is exempt from OOM kill) into a situation where possibly
> all of the database processes are exempt from OOM kill, at the whim
> of somebody who should not have the privilege to decide that.
Meh^3. By that argument we need to forbid superusers to create any form
of untrusted functions. Forbid anything that does malloc(), system(),
fork(), whatever from a user's influence.
Superusers can execute code in the postmaster using
shared_preload_libraries. Feigning that that's not possible isn't buying
us anything.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: andres@2ndquadrant.com, tgl@sss.pgh.pa.us, robertmhaas@gmail.com, gurjeet@singh.im, peter_e@gmx.net
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels
In-Reply-To: <20140610152419.GL8406@alap3.anarazel.de>
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