From: Stephen Hemminger <stephen@networkplumber.org>
To: Lubomir Rintel <lkundrak@v3.sk>
Cc: netdev@vger.kernel.org, Phil Sutter <phil@nwl.cc>
Subject: Re: [iproute PATCH] lib/namespace: avoid double-mounting a /sys
Date: Fri, 27 Jul 2018 13:45:05 -0700 [thread overview]
Message-ID: <20180727134505.4065994f@xeon-e3> (raw)
In-Reply-To: <20180724172638.760873-1-lkundrak@v3.sk>
On Tue, 24 Jul 2018 19:26:38 +0200
Lubomir Rintel <lkundrak@v3.sk> wrote:
> This partly reverts 8f0807023d067e2bb585a2ae8da93e59689d10f1, bringing
> back the umount(/sys) attempt.
>
> In a LXC container we're unable to umount the sysfs instance, nor mount
> a read-write one. We still are able to create a new read-only instance.
>
> Nevertheless, it still makes sense to attempt the umount() even though
> the sysfs is mounted read-only. Otherwise we may end up attempting to
> mount a sysfs with the same flags as is already mounted, resulting in
> an EBUSY error (meaning "Already mounted").
>
> Perhaps this is not a very likely scenario in real world, but we hit
> it in NetworkManager test suite and makes netns_switch() somewhat more
> robust. It also fixes the case, when /sys wasn't mounted at all.
>
> Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Makes sens applied.
prev parent reply other threads:[~2018-07-27 22:08 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-24 17:26 [iproute PATCH] lib/namespace: avoid double-mounting a /sys Lubomir Rintel
2018-07-27 20:45 ` Stephen Hemminger [this message]
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