Linux-man Archive on
 help / color / Atom feed
From: Christian Brauner <>
To:, Florian Weimer <>,
	Szabolcs Nagy <>
Cc: Adhemerval Zanella <>,
	"" <>,
	nd <>, linux-man <>
Subject: Re: glibc in master is incompatible with systemd-nspawn
Date: Fri, 08 Nov 2019 17:23:37 +0100
Message-ID: <> (raw)
In-Reply-To: <>

On November 8, 2019 5:19:47 PM GMT+01:00, Florian Weimer <> wrote:
>* Szabolcs Nagy:
>> it's of course broken whenever the application is
>> run on a newer kernel+libc than what was used for
>> creating the filter, may be the seccomp manual should
>> warn against the use of EPERM (there is already a
>> caveats section)?
>On this topic (ENOSYS vs PERM), I wrote earlier today:
>| They serve different purposes. EPERM is appropriate if you want
>| to fail (so that applications break), ENOSYS is appropriate if you
>| want to trigger fallback (like utimensat_time64 → utime) or just
>| disable the feature (because the application assumes the kernel is
>| old to support it). For a generic container runtime, there either
>| to be no filters by default (my preference), or filters for unknown
>| system calls need to return ENOSYS. Everything else will break too
>| many applications.
>| If you have specific knowledge of the system call, you can return
>| EPERM instead in a few cases (e.g. for clock_settime). But that's not
>| really possible for an unknown system call.
>I don't know how controversial this position is.  People seem rather
>opinionated about EPERM.

Fwiw, with LXC and LXD we use ENOSYS.
I chatted with Lennart about this a few minutes ago.

      reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
     [not found]   ` <>
     [not found]     ` <>
2019-11-08 16:01       ` Szabolcs Nagy
2019-11-08 16:19         ` Florian Weimer
2019-11-08 16:23           ` Christian Brauner [this message]

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-man Archive on

Archives are clonable:
	git clone --mirror linux-man/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-man linux-man/ \
	public-inbox-index linux-man

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone