From: Cyrill Gorcunov <gorcunov@openvz.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Pavel Emelyanov <xemul@parallels.com>,
Andrey Vagin <avagin@openvz.org>,
KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Glauber Costa <glommer@parallels.com>,
Andi Kleen <andi@firstfloor.org>, Tejun Heo <tj@kernel.org>,
Matt Helsley <matthltc@us.ibm.com>,
Pekka Enberg <penberg@kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
Vasiliy Kulikov <segoon@openwall.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Valdis.Kletnieks@vt.edu, Michal Marek <mmarek@suse.cz>,
Frederic Weisbecker <fweisbec@gmail.com>,
linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>
Subject: Re: + syscalls-x86-add-__nr_kcmp-syscall-v8.patch added to -mm tree
Date: Wed, 11 Apr 2012 02:54:31 +0400 [thread overview]
Message-ID: <20120410225431.GN24857@moon> (raw)
In-Reply-To: <m1ehrwb74t.fsf@fess.ebiederm.org>
On Mon, Apr 09, 2012 at 08:25:22PM -0700, Eric W. Biederman wrote:
...
>
> Having just read through it again the only possible issue I can see is
> that we compare file descriptors after dropping all of the locks.
>
> Since rcu_read_lock doesn't participate in ABBA deadlocks. My gut feel
> is that we should hold rcu_read_lock across the hole file pointer
> comparison to remove the possibility of races as file descriptor
> pointers go away.
>
> Still in practice I don't think it matters. At worst there is the
> slightest possibility of returning a value instead of -EBADF. The
> expectation is for all of the tasks we are operating on to be frozen,
> and even if the tasks are not frozen it is a very tiny window for a race
> to be in.
yeah, we use this call heavily on stopped tasks atm
> > So what do people think? Any issues? Any nacks? Should I sneak it
> > into Linus this week or do we need to go another round with it all?
>
> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>
Thanks a lot, Eric!
Cyrill
next prev parent reply other threads:[~2012-04-10 22:54 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-15 14:36 + syscalls-x86-add-__nr_kcmp-syscall-v8.patch added to -mm tree Oleg Nesterov
2012-02-15 15:10 ` Cyrill Gorcunov
2012-02-15 15:38 ` Oleg Nesterov
2012-02-15 16:13 ` Cyrill Gorcunov
2012-02-15 16:22 ` Oleg Nesterov
2012-02-15 17:53 ` Cyrill Gorcunov
2012-02-15 18:43 ` Oleg Nesterov
2012-02-15 19:56 ` Cyrill Gorcunov
2012-02-15 19:57 ` Vasiliy Kulikov
2012-02-15 20:05 ` Cyrill Gorcunov
2012-02-15 20:25 ` Cyrill Gorcunov
2012-02-15 21:09 ` Cyrill Gorcunov
2012-02-15 21:58 ` Cyrill Gorcunov
2012-02-16 14:49 ` Oleg Nesterov
2012-02-16 15:13 ` Cyrill Gorcunov
2012-02-16 16:49 ` Cyrill Gorcunov
2012-02-16 17:40 ` Oleg Nesterov
2012-02-16 17:58 ` Cyrill Gorcunov
2012-02-16 19:03 ` Oleg Nesterov
2012-02-16 19:20 ` H. Peter Anvin
2012-02-16 19:29 ` Cyrill Gorcunov
2012-02-16 19:52 ` Andrew Morton
2012-02-16 20:01 ` Cyrill Gorcunov
2012-02-16 18:21 ` Vasiliy Kulikov
2012-02-16 18:34 ` Cyrill Gorcunov
2012-02-16 18:33 ` Vasiliy Kulikov
2012-02-16 18:49 ` Oleg Nesterov
2012-02-15 18:32 ` Cyrill Gorcunov
2012-02-15 19:06 ` Oleg Nesterov
2012-02-15 19:18 ` Cyrill Gorcunov
2012-02-15 16:06 ` Oleg Nesterov
2012-02-15 16:27 ` Cyrill Gorcunov
2012-04-09 22:10 ` Andrew Morton
2012-04-09 22:24 ` Cyrill Gorcunov
2012-04-09 23:22 ` H. Peter Anvin
2012-04-10 22:37 ` Cyrill Gorcunov
2012-04-10 22:39 ` H. Peter Anvin
2012-04-10 22:48 ` Cyrill Gorcunov
2012-04-10 23:08 ` Oleg Nesterov
2012-04-10 23:32 ` H. Peter Anvin
2012-04-10 23:42 ` Oleg Nesterov
2012-04-11 6:39 ` Cyrill Gorcunov
2012-04-11 18:31 ` Oleg Nesterov
2012-04-11 0:02 ` Valdis.Kletnieks
2012-04-10 3:25 ` Eric W. Biederman
2012-04-10 22:54 ` Cyrill Gorcunov [this message]
2012-04-10 23:58 ` Valdis.Kletnieks
2012-04-11 0:06 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2012-02-14 23:15 akpm
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