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Message-ID: <1518008590.3677.126.camel@infradead.org>
Subject: Re: [PATCH] mm: Always print RLIMIT_DATA warning
From:   David Woodhouse <dwmw2@infradead.org>
To:     Konstantin Khlebnikov <koct9i@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Vegard Nossum <vegard.nossum@oracle.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Vladimir Davydov <vdavydov@virtuozzo.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Quentin Casasnovas <quentin.casasnovas@oracle.com>,
        Kees Cook <keescook@google.com>, Willy Tarreau <w@1wt.eu>,
        Pavel Emelyanov <xemul@virtuozzo.com>,
        Laura Abbott <labbott@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-mm@kvack.org
In-Reply-To: <CALYGNiOUZXiOeWSYMgeF3792NNWAgpcxnAOMQ_Wb-d1-Xo_k0Q@mail.gmail.com>
References: <1517935505-9321-1-git-send-email-dwmw@amazon.co.uk>
         <CALYGNiOUZXiOeWSYMgeF3792NNWAgpcxnAOMQ_Wb-d1-Xo_k0Q@mail.gmail.com>
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Date:   Wed, 07 Feb 2018 13:03:10 +0000
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On Tue, 2018-02-06 at 20:48 +0300, Konstantin Khlebnikov wrote:
> On Tue, Feb 6, 2018 at 7:45 PM, David Woodhouse <dwmw@amazon.co.uk> wrote=
:
> >=20
> > The documentation for ignore_rlimit_data says that it will print a warn=
ing
> > at first misuse. Yet it doesn't seem to do that. Fix the code to print
> > the warning even when we allow the process to continue.
>
> Ack. But I think this was a misprint in docs.
> Anyway, this knob is a kludge so we might warn once even if it is set.

Right. I think we definitely should. Otherwise, once set, there's no
real path to ever being able to *unset* it. Nothing well ever get
fixed.

> So, somebody still have problems with this change?
> I remember concerns about that "warn_once" isn't enough to detect
> what's going wrong.
> And probably we should invent=C2=A0=C2=A0"warn_sometimes".

That was covered by "should probably also do what Linus suggested=E2=80=A6"=
:

> > ---
> > We should probably also do what Linus suggested in
> > https://lkml.org/lkml/2016/9/16/585

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