netdev - Re: [PATCH] Fix: Preserve /sys hierarchy in network namespaces

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Date: Mon, 8 May 2023 17:41:15 +0200
From: Andrew Lunn <andrew@...n.ch>
To: Bilal Khan <bilalkhanrecovered@...il.com>
Cc: Stephen Hemminger <stephen@...workplumber.org>,
	majordomo@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH] Fix: Preserve /sys hierarchy in network namespaces

On Mon, May 08, 2023 at 08:05:37PM +0500, Bilal Khan wrote:
> Dear Maintainer,
> 
> I have come across an issue with the way network namespaces are
> created by ip-netns(8) in Ubuntu 18.04.4 LTS. The problem occurs when
> the /sys hierarchy, particularly /sys/fs/cgroup, is not properly
> mounted within network namespaces. This issue can be traced back to
> the netns_switch() function in the lib/namespace.c file, where /sys is
> explicitly unmounted and mounted again.
> 
> I have created a patch to fix this issue, which removes the calls to
> umount2() and mount() related to the /sys filesystem in the
> netns_switch() function.

Hi Bilal

It would be good to explain in the commit message why this
unount/mount is no longer needed. Can you point at a kernel commit
which makes this no longer required?

      Andrew