From: Oleg Nesterov <oleg@redhat.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Kees Cook <keescook@chromium.org>, Tejun Heo <tj@kernel.org>,
Andrew Vagin <avagin@openvz.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Pavel Emelyanov <xemul@parallels.com>,
Vasiliy Kulikov <segoon@openwall.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Julien Tinnes <jln@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: + prctl-pr_set_mm-introduce-pr_set_mm_map-operation-v3.patch added to -mm tree
Date: Sat, 23 Aug 2014 15:30:01 +0200 [thread overview]
Message-ID: <20140823133001.GA966@redhat.com> (raw)
In-Reply-To: <20140823131412.GA31685@redhat.com>
forgot to mention,
On 08/23, Oleg Nesterov wrote:
>
> On 08/23, Cyrill Gorcunov wrote:
>
> > Looks like I need
> > to use cred_guard_mutex instead of task_lock here, no?
>
> Please don't. First of all, it can't help because proc_pid_auxv() doesn't hold
> this lock. It does mm_access() which drops this lock after return. And to remind,
> we are going to remove mm_access/lock_trace from sys_read() paths in proc.
Besides, it can't help anyway. cred_guard_mutex is per-process (not per-thread),
suppose that a vfork()'ed child does prctl() while another thread reads the
parent's /proc/pid/auxv.
Cyrill, I am sorry, but I am starting to think that this patch should be
dropped and replaced by another version. Or do you think it would be better
to send the fixes on top?
Oleg.
next prev parent reply other threads:[~2014-08-23 13:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-22 19:22 + prctl-pr_set_mm-introduce-pr_set_mm_map-operation-v3.patch added to -mm tree Oleg Nesterov
2014-08-22 20:15 ` Cyrill Gorcunov
2014-08-23 11:53 ` Oleg Nesterov
2014-08-23 12:22 ` Cyrill Gorcunov
2014-08-23 13:14 ` Oleg Nesterov
2014-08-23 13:30 ` Oleg Nesterov [this message]
2014-08-23 14:18 ` Cyrill Gorcunov
2014-08-23 15:32 ` Oleg Nesterov
2014-08-23 16:33 ` Cyrill Gorcunov
2014-08-23 19:29 ` Oleg Nesterov
2014-08-23 20:11 ` Cyrill Gorcunov
-- strict thread matches above, loose matches on Subject: below --
2014-08-21 22:51 akpm
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