From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
To: Mike Frysinger <vapier@gentoo.org>
Cc: mtk.manpages@gmail.com, linux-man@vger.kernel.org
Subject: Re: [PATCH] setns.2: fix CLONE_NEWNS restriction info
Date: Thu, 19 Sep 2019 08:38:36 +0200 [thread overview]
Message-ID: <0f6c29d9-5c1f-acf4-c771-3c780961bb0b@gmail.com> (raw)
In-Reply-To: <20190919054342.5405-1-vapier@gentoo.org>
Hello Mike,
On 9/19/19 7:43 AM, Mike Frysinger wrote:
> Threads are allowed to switch mount namespaces if the filesystem
> details aren't being shared. That's the purpose of the check in
> the kernel quoted by the comment:
> if (fs->users != 1)
> return -EINVAL;
>
> It's been this way since the code was originally merged in v3.8.
Thanks. Patch applied.
Cheers,
Michael
> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
> ---
> man2/setns.2 | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/man2/setns.2 b/man2/setns.2
> index 18e80202326a..5985c099b464 100644
> --- a/man2/setns.2
> +++ b/man2/setns.2
> @@ -131,8 +131,12 @@ capabilities in its own user namespace and
> .BR CAP_SYS_ADMIN
> in the user namespace that owns the target mount namespace.
> .IP
> -A process may not be reassociated with a new mount namespace if it is
> -multithreaded.
> +A process can't join a new mount namespace if it is sharing
> +filesystem-related attributes
> +(the attributes whose sharing is controlled by the
> +.BR clone (2)
> +.B CLONE_FS
> +flag) with another process.
> .\" Above check is in fs/namespace.c:mntns_install() [3.8 source]
> .IP
> See
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
prev parent reply other threads:[~2019-09-19 6:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 5:43 [PATCH] setns.2: fix CLONE_NEWNS restriction info Mike Frysinger
2019-09-19 6:38 ` Michael Kerrisk (man-pages) [this message]
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