From: Alexey Gladkov <gladkov.alexey-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
Linux Kernel Mailing List
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Kirill A. Shutemov"
<kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>,
Vasiliy Kulikov <segoon-cxoSlKxDwOJWk0Htik3J/w@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
"Eric W. Biederman"
<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>,
James Bottomley
<James.Bottomley-JuX6DAaQMKPCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>,
"Dmitry V. Levin" <ldv-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org>
Subject: Re: [RFC] Add option to mount only a pids subset
Date: Sat, 11 Mar 2017 22:51:02 +0100 [thread overview]
Message-ID: <20170311215102.GF4554@comp-core-i7-2640m-0182e6> (raw)
In-Reply-To: <CAEiveUczqzHZG7jcM72oWXAKYZSPJ0ywYEXGDV1sn_FAhr28pA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Thu, Mar 09, 2017 at 12:26:49PM +0100, Djalal Harouni wrote:
> I'm bit lost in the two discussion, however the main concern I was
> discussing with Andy was if you have per superblock proc mounts then
> each mount will end up with its own device ID st_dev, right now they
> share the same ID if they are in the same pid namespace, but if we
> change that then we may break the following:
> http://man7.org/linux/man-pages/man7/namespaces.7.html
In fact, nothing has changed. I added a parameter that affects
the mountpoint, not the entire pid namespace.
The procfs will still be global. The device ID will be the same as before.
> Both new NS_GET_PARENT and NS_GET_USERNS ioctl() that return an fd,
> suggests to follow up with fstat() to identify the namespaces..
> "By applying fstat(2) to the returned file descriptor, one obtains a
> stat structure whose st_dev (resident device) and st_ino (inode
> number) fields together identify the owning/parent namespace."
>
> Other /proc/self/ns/* comparison and stat() logic...
>
> Andy suggested that we may have the same st_dev for mounts in the same
> pid namespace... I'm not sure which side effect this may bring!
Basically we have here a issue because other proc options (hidepid for
example) affect the entire pid namespace, but, I guess, have to affect
the mountpoint.
# grep ^proc /proc/mounts
proc /proc proc rw,relatime 0 0
# mount -t proc proc /tmp/proc
# mount -o remount,hidepid=2 -t proc proc /tmp/proc
# grep ^proc /proc/mounts
proc /proc proc rw,relatime,hidepid=2 0 0
proc /tmp/proc proc rw,relatime,hidepid=2 0 0
--
Rgrds, legion
next prev parent reply other threads:[~2017-03-11 21:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170221145746.GA31914@redhat.com>
[not found] ` <20170221145746.GA31914-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-03-06 23:05 ` [RFC] Add option to mount only a pids subset Alexey Gladkov
2017-03-07 16:24 ` Andy Lutomirski
2017-03-09 11:26 ` Djalal Harouni
[not found] ` <CAEiveUczqzHZG7jcM72oWXAKYZSPJ0ywYEXGDV1sn_FAhr28pA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-09 20:52 ` Eric W. Biederman
2017-03-11 21:51 ` Alexey Gladkov [this message]
[not found] ` <CALCETrVFnSoBP+LvyjN+1qUqrwgZan1nvscq5hV0Ujt_FF2e3g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-11 0:05 ` Alexey Gladkov
2017-03-07 17:49 ` Oleg Nesterov
[not found] ` <20170307174909.GA24112-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-03-10 23:46 ` Alexey Gladkov
2017-03-12 1:54 ` Al Viro
[not found] ` <20170312015430.GO29622-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-03-12 2:13 ` Al Viro
[not found] ` <20170312021257.GP29622-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-03-13 3:19 ` Andy Lutomirski
[not found] ` <CALCETrVT5sfGhNomLKAephrSGj8fc81ZjGTN-Y6UwgAHngVRCA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-13 13:27 ` Al Viro
[not found] ` <20170313132732.GR29622-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-03-13 15:24 ` Andy Lutomirski
[not found] ` <CALCETrXqv8VUeO6MpKWDR6DFYBgmmT0nZVezBJsimtmmQgDksw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-23 15:59 ` [PATCH] proc: allow to change proc mount options per mount Djalal Harouni
2017-03-20 12:58 ` [RFC] Add option to mount only a pids subset Alexey Gladkov
2017-03-23 16:05 ` Oleg Nesterov
[not found] ` <20170323160507.GA23135-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-03-23 22:57 ` Alexey Gladkov
2017-03-23 16:06 ` Djalal Harouni
2017-03-23 22:07 ` Alexey Gladkov
2017-03-26 7:03 ` Djalal Harouni
[not found] ` <CAEiveUe15YvZ4hMYSPgm586MkJ20PO515r9krXdjPCUmrG1wSA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-30 21:45 ` Alexey Gladkov
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