From: Oleg Nesterov <oleg@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>, Ying Han <yinghan@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Roland McGrath <roland@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
JANAK DESAI <janak@us.ibm.com>
Subject: Re: [PATCH 1/1][2nd resend] sys_unshare: remove the dead CLONE_THREAD/SIGHAND/VM code
Date: Tue, 9 Nov 2010 18:17:54 +0100 [thread overview]
Message-ID: <20101109171754.GB6971@redhat.com> (raw)
In-Reply-To: <20101109201742.BCA1.A69D9226@jp.fujitsu.com>
On 11/09, KOSAKI Motohiro wrote:
>
> > -static void check_unshare_flags(unsigned long *flags_ptr)
> > +static int check_unshare_flags(unsigned long unshare_flags)
> > {
> > + if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
> > + CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
> > + CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET))
> > + return -EINVAL;
>
> Please put WARN_ON_ONCE() explicitly. That's good way to find hidden
> user if exist and getting better bug report.
Perhaps... but this needs a separate change.
Please note that this check was simply moved from sys_unshare(), this
patch shouldn't have any visible effect.
Personally, I think it would be even better if, say, unshare(CLONE_THREAD)
returned -EINVAL unconditionally.
> And, I've reveied this patch and I've found no fault. but I will not put
> my ack because I think I haven't understand original intention perhaps.
Thanks!
IIRC, the main (only?) motivation for sys_unshare() was unshare_fs().
Most probably unshare_thread/vm were added as placeholders.
Oleg.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>, Ying Han <yinghan@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Roland McGrath <roland@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
JANAK DESAI <janak@us.ibm.com>
Subject: Re: [PATCH 1/1][2nd resend] sys_unshare: remove the dead CLONE_THREAD/SIGHAND/VM code
Date: Tue, 9 Nov 2010 18:17:54 +0100 [thread overview]
Message-ID: <20101109171754.GB6971@redhat.com> (raw)
In-Reply-To: <20101109201742.BCA1.A69D9226@jp.fujitsu.com>
On 11/09, KOSAKI Motohiro wrote:
>
> > -static void check_unshare_flags(unsigned long *flags_ptr)
> > +static int check_unshare_flags(unsigned long unshare_flags)
> > {
> > + if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
> > + CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
> > + CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET))
> > + return -EINVAL;
>
> Please put WARN_ON_ONCE() explicitly. That's good way to find hidden
> user if exist and getting better bug report.
Perhaps... but this needs a separate change.
Please note that this check was simply moved from sys_unshare(), this
patch shouldn't have any visible effect.
Personally, I think it would be even better if, say, unshare(CLONE_THREAD)
returned -EINVAL unconditionally.
> And, I've reveied this patch and I've found no fault. but I will not put
> my ack because I think I haven't understand original intention perhaps.
Thanks!
IIRC, the main (only?) motivation for sys_unshare() was unshare_fs().
Most probably unshare_thread/vm were added as placeholders.
Oleg.
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next prev parent reply other threads:[~2010-11-09 17:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <201010262121.o9QLLNFo016375@imap1.linux-foundation.org>
[not found] ` <20101101024949.6074.A69D9226@jp.fujitsu.com>
[not found] ` <alpine.DEB.2.00.1011011738200.26266@chino.kir.corp.google.com>
2010-11-03 0:41 ` [patch v2] oom: fix oom_score_adj consistency with oom_disable_count David Rientjes
2010-11-03 11:23 ` Oleg Nesterov
2010-11-03 20:28 ` David Rientjes
2010-11-04 18:42 ` Oleg Nesterov
2010-11-05 17:41 ` [PATCH 0/1] (Was: oom: fix oom_score_adj consistency with oom_disable_count) Oleg Nesterov
2010-11-05 17:41 ` Oleg Nesterov
2010-11-05 17:43 ` [PATCH 1/1][2nd resend] sys_unshare: remove the dead CLONE_THREAD/SIGHAND/VM code Oleg Nesterov
2010-11-05 17:43 ` Oleg Nesterov
2010-11-09 11:21 ` KOSAKI Motohiro
2010-11-09 11:21 ` KOSAKI Motohiro
2010-11-09 17:17 ` Oleg Nesterov [this message]
2010-11-09 17:17 ` Oleg Nesterov
2010-11-14 7:14 ` KOSAKI Motohiro
2010-11-14 7:14 ` KOSAKI Motohiro
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