From: Florian Weimer <fweimer@redhat.com>
To: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
"libc-alpha\@sourceware.org" <libc-alpha@sourceware.org>,
nd <nd@arm.com>, linux-man <linux-man@vger.kernel.org>
Subject: Re: glibc in master is incompatible with systemd-nspawn
Date: Fri, 08 Nov 2019 17:19:47 +0100 [thread overview]
Message-ID: <874kze1gt8.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <e3486649-58fa-c1b5-7913-9e9f098972db@arm.com> (Szabolcs Nagy's message of "Fri, 8 Nov 2019 16:01:58 +0000")
* 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 things
| 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 too
| old to support it). For a generic container runtime, there either have
| 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.
<https://bugzilla.redhat.com/show_bug.cgi?id=1769299>
I don't know how controversial this position is. People seem rather
opinionated about EPERM.
Thanks,
Florian
next prev parent reply other threads:[~2019-11-08 16:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87k18a62xe.fsf@oldenburg2.str.redhat.com>
[not found] ` <20191108141149.GB20533@altlinux.org>
[not found] ` <87v9ru1l6d.fsf@oldenburg2.str.redhat.com>
[not found] ` <c4001320-2d3f-9523-c93f-60f799545654@linaro.org>
2019-11-08 16:01 ` glibc in master is incompatible with systemd-nspawn Szabolcs Nagy
2019-11-08 16:19 ` Florian Weimer [this message]
2019-11-08 16:23 ` Christian Brauner
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