From: David Laight <David.Laight@ACULAB.COM>
To: 'Alexey Dobriyan' <adobriyan@gmail.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: RE: setns() affecting other threads in 5.10.132 and 6.0
Date: Tue, 6 Sep 2022 10:48:16 +0000 [thread overview]
Message-ID: <6204a74ef41a4463a790962d0409d0bc@AcuMS.aculab.com> (raw)
In-Reply-To: <YxYytPTFwYr7vBTo@localhost.localdomain>
From: Alexey Dobriyan
> Sent: 05 September 2022 18:33
> > > -----Original Message-----
> > > From: David Laight <David.Laight@ACULAB.COM>
> > > Sent: 04 September 2022 15:05
> > >
> > > Sometime after 5.10.105 (5.10.132 and 6.0) there is a change that
> > > makes setns(open("/proc/1/ns/net")) in the main process changes
> > > the behaviour of other process threads.
>
> Not again...
I've realised what is going on.
It really isn't obvious at all.
Quite possibly the last change did fix it - even though
it broke our code.
/proc/net is a symlink to /proc/self/net.
But that isn't what the code wants to open.
What it needs is /proc/self/task/self/net.
But there isn't a 'self' in /proc/self/task.
Which makes it all a bit tedious (especially without gettid() in glibc).
(This is a busybox/buildroot system, maybe I could add it!)
I'd probably have noticed earlier if the /proc/net
symlink didn't exist.
I guess that is for compatibility with pre-netns kernels.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2022-09-06 10:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-04 14:05 setns() affecting other threads in 5.10.132 and 6.0 David Laight
2022-09-05 7:11 ` Greg KH
2022-09-05 9:54 ` David Laight
2022-09-05 17:32 ` Alexey Dobriyan
2022-09-06 8:25 ` David Laight
2022-09-06 10:48 ` David Laight [this message]
2022-09-29 9:33 ` setns() affecting other threads in 5.10.132 and 6.0 #forregzbot Thorsten Leemhuis
2022-09-05 10:32 ` setns() affecting other threads in 5.10.132 and 6.0 Thorsten Leemhuis
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