From: Andres Freund <andres@anarazel.de>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org
Subject: Re: io_uring_setup spuriously returning ENOMEM for one user
Date: Thu, 16 Jul 2020 13:20:02 -0700 [thread overview]
Message-ID: <20200716202002.ccuidrqbknvzhxiv@alap3.anarazel.de> (raw)
In-Reply-To: <af57a2d2-86d2-96f7-5f63-19b02d800e71@gmail.com>
Hi,
On 2020-07-16 23:12:41 +0300, Pavel Begunkov wrote:
> On 16/07/2020 23:05, Andres Freund wrote:
> > Hi,
> >
> > While testing the error handling of my uring using postgres branch I
> > just encountered the situation that io_uring_setup() always fails with
> > ENOMEN.
> >
> > It only does so for the user I did the testing on and not for other
> > users. During the testing a few io_uring using processes were kill -9'd
> > and a few core-dumped after abort(). No io_uring using processes are
> > still alive.
> >
> > As the issue only happens to the one uid I suspect that
> > current_user()->locked_mem got corrupted, perhaps after hitting the
> > limit for real.
>
> Any chance it's using SQPOLL mode?
No. It's a "plain" uring. The only thing that could be considered
special is that one of the rings is shared between processes (which all
run as the same user).
Greetings,
Andres Freund
next prev parent reply other threads:[~2020-07-16 20:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 20:05 io_uring_setup spuriously returning ENOMEM for one user Andres Freund
2020-07-16 20:12 ` Pavel Begunkov
2020-07-16 20:20 ` Andres Freund [this message]
2020-07-16 20:31 ` Jens Axboe
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