From: Christian Brauner <christian@brauner.io>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Andy Lutomirski <luto@amacapital.net>,
Daniel Colascione <dancol@google.com>,
Jann Horn <jannh@google.com>, Andrew Lutomirski <luto@kernel.org>,
David Howells <dhowells@redhat.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
Linux API <linux-api@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
Kees Cook <keescook@chromium.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Michael Kerrisk-manpages <mtk.manpages@gmail.com>,
Jonathan Kowalski <bl0pbl33p@gmail.com>,
"Dmitry V. Levin" <ldv@altlinux.org>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>,
Aleksa Sarai <cyphar@cyphar.com>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH v2 0/5] pid: add pidfd_open()
Date: Mon, 1 Apr 2019 02:21:49 +0200 [thread overview]
Message-ID: <20190401002147.vv23md5spi34uyjz@brauner.io> (raw)
In-Reply-To: <CAHk-=wi39-Ozq5zb22s7ZB4J_Nd6nTwE_9A3+qjp5nCY4iTSEg@mail.gmail.com>
On Sun, Mar 31, 2019 at 05:18:10PM -0700, Linus Torvalds wrote:
> On Sun, Mar 31, 2019 at 5:09 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > Ugh... Which vfsmount would you have to go with it?
>
> I'd literally just do a lookup of "/proc" in the current root
> directory in the lookup() function for that special pseudo-dentry.
>
> If it's not mounted, or not a /proc filesystem, screw it.
>
> > Except that we never let unattached _directory_ dentries out - if
> > we can't reattach them to the tree, open-by-handle will tell you to
> > take a hike.
>
> Absolutely. Which is why I said it's _conceptually_ similar to the alias lookup.
>
> And I suspect we can even use some of the same practical logic, but
> it's definitely not _exactly_ the same. This thing very much involves
> magic hooking into the lookup() function (but we then have to look up
> the alias not for the path we're looking up, but for the _parent_
> we're looking that path up in, which is very different from the normal
> case).
>
> > It's more than a tiny bit too clever for mine...
>
> Fair enough. The whole "just do the whole lookup at pidfd creation
> time" is certainly a whole lot simpler.
Even just from a pure maintenance perspective this sounds a better to me.
next prev parent reply other threads:[~2019-04-01 0:22 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-29 15:54 [PATCH v2 0/5] pid: add pidfd_open() Christian Brauner
2019-03-29 15:54 ` [PATCH v2 1/5] Make anon_inodes unconditional Christian Brauner
2019-03-29 15:54 ` [PATCH v2 2/5] pid: add pidfd_open() Christian Brauner
2019-03-29 23:45 ` Jann Horn
2019-03-29 23:55 ` Christian Brauner
2019-03-30 11:53 ` Jürg Billeter
2019-03-30 14:37 ` Christian Brauner
2019-03-30 14:51 ` Jonathan Kowalski
2019-03-29 15:54 ` [PATCH v2 3/5] signal: support pidfd_open() with pidfd_send_signal() Christian Brauner
2019-03-29 15:54 ` [PATCH v2 4/5] signal: PIDFD_SIGNAL_TID threads via pidfds Christian Brauner
2019-03-30 1:06 ` Jann Horn
2019-03-30 1:22 ` Christian Brauner
2019-03-30 1:34 ` Christian Brauner
2019-03-30 1:42 ` Christian Brauner
2019-03-29 15:54 ` [PATCH v2 5/5] tests: add pidfd_open() tests Christian Brauner
2019-03-30 16:09 ` [PATCH v2 0/5] pid: add pidfd_open() Linus Torvalds
2019-03-30 16:11 ` Daniel Colascione
2019-03-30 16:16 ` Linus Torvalds
2019-03-30 16:18 ` Linus Torvalds
2019-03-31 1:07 ` Joel Fernandes
2019-03-31 2:34 ` Jann Horn
2019-03-31 4:08 ` Joel Fernandes
2019-03-31 4:46 ` Jann Horn
2019-03-31 14:52 ` Linus Torvalds
2019-03-31 15:05 ` Christian Brauner
2019-03-31 15:21 ` Daniel Colascione
2019-03-31 15:33 ` Jonathan Kowalski
2019-03-30 16:19 ` Christian Brauner
2019-03-30 16:24 ` Linus Torvalds
2019-03-30 16:34 ` Daniel Colascione
2019-03-30 16:38 ` Christian Brauner
2019-03-30 17:04 ` Linus Torvalds
2019-03-30 17:12 ` Christian Brauner
2019-03-30 17:24 ` Linus Torvalds
2019-03-30 17:37 ` Christian Brauner
2019-03-30 17:50 ` Jonathan Kowalski
2019-03-30 17:52 ` Christian Brauner
2019-03-30 17:59 ` Jonathan Kowalski
2019-03-30 18:02 ` Christian Brauner
2019-03-30 18:00 ` Jann Horn
2019-03-31 20:09 ` Andy Lutomirski
2019-03-31 21:03 ` Linus Torvalds
2019-03-31 21:10 ` Christian Brauner
2019-03-31 21:17 ` Linus Torvalds
2019-03-31 22:03 ` Christian Brauner
2019-03-31 22:16 ` Linus Torvalds
2019-03-31 22:33 ` Christian Brauner
2019-04-01 0:52 ` Jann Horn
2019-04-01 8:47 ` Yann Droneaud
2019-04-01 10:03 ` Jonathan Kowalski
2019-03-31 23:40 ` Linus Torvalds
2019-04-01 0:09 ` Al Viro
2019-04-01 0:18 ` Linus Torvalds
2019-04-01 0:21 ` Christian Brauner [this message]
2019-04-01 6:37 ` Al Viro
2019-04-01 6:41 ` Al Viro
2019-03-31 22:03 ` Jonathan Kowalski
2019-04-01 2:13 ` Andy Lutomirski
2019-04-01 11:40 ` Aleksa Sarai
2019-04-01 15:36 ` Linus Torvalds
2019-04-01 15:47 ` Christian Brauner
2019-04-01 15:55 ` Daniel Colascione
2019-04-01 16:01 ` Linus Torvalds
2019-04-01 16:13 ` Daniel Colascione
2019-04-01 19:42 ` Christian Brauner
2019-04-01 21:30 ` Linus Torvalds
2019-04-01 21:58 ` Jonathan Kowalski
2019-04-01 22:13 ` Linus Torvalds
2019-04-01 22:34 ` Daniel Colascione
2019-04-01 16:07 ` Jonathan Kowalski
2019-04-01 16:15 ` Linus Torvalds
2019-04-01 16:27 ` Jonathan Kowalski
2019-04-01 16:21 ` Daniel Colascione
2019-04-01 16:29 ` Linus Torvalds
2019-04-01 16:45 ` Daniel Colascione
2019-04-01 17:00 ` David Laight
2019-04-01 17:32 ` Linus Torvalds
2019-04-02 11:03 ` Florian Weimer
2019-04-01 16:10 ` Andy Lutomirski
2019-04-01 12:04 ` Christian Brauner
2019-04-01 13:43 ` Jann Horn
2019-03-31 21:19 ` Christian Brauner
2019-03-30 16:37 ` Christian Brauner
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