From: David Howells <dhowells@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: dhowells@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alexander Gordeev <agordeev@redhat.com>,
Chris Zankel <chris@zankel.net>, David Smith <dsmith@redhat.com>,
"Frank Ch. Eigler" <fche@redhat.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Larry Woodman <lwoodman@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Richard Kuo <rkuo@codeaurora.org>, Tejun Heo <tj@kernel.org>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 4/6] keys: change keyctl_session_to_parent() to use task_work_add()
Date: Fri, 20 Apr 2012 09:45:16 +0100 [thread overview]
Message-ID: <10220.1334911516@redhat.com> (raw)
In-Reply-To: <20120419231543.GD15828@redhat.com>
Oleg Nesterov <oleg@redhat.com> wrote:
> Change keyctl_session_to_parent() to use task_work_add() and
> move key_replace_session_keyring() logic into task_work->func().
>
> Note that we do task_work_cancel() before task_work_add() to
> ensure that only one work can be pending at any time. This is
> important, we must not allow user-space to abuse the parent's
> ->task_works list.
>
> The callback, replace_session_keyring(), checks PF_EXITING.
> I guess this is not really needed but looks better.
>
> As a side effect, this fixes the (unlikely) race. The callers
> of key_replace_session_keyring() and keyctl_session_to_parent()
> lack the necessary barriers, the parent can miss the request.
>
> Now we can remove task_struct->replacement_session_keyring and
> related code.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
next prev parent reply other threads:[~2012-04-20 8:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-19 23:14 [PATCH v6 0/6] task_work_add: generic process-context callbacks Oleg Nesterov
2012-04-19 23:14 ` [PATCH v6 1/6] " Oleg Nesterov
2012-04-20 8:48 ` David Howells
2012-04-19 23:15 ` [PATCH v6 2/6] genirq: reimplement exit_irq_thread() hook via task_work_add() Oleg Nesterov
2012-04-19 23:15 ` [PATCH v6 3/6] hexagon: do_notify_resume() needs tracehook_notify_resume() Oleg Nesterov
2012-04-20 0:24 ` Richard Kuo
2012-04-19 23:15 ` [PATCH v6 4/6] keys: change keyctl_session_to_parent() to use task_work_add() Oleg Nesterov
2012-04-20 8:45 ` David Howells [this message]
2012-04-19 23:16 ` [PATCH v6 5/6] keys: kill the dummy key_replace_session_keyring() Oleg Nesterov
2012-04-20 8:45 ` David Howells
2012-04-19 23:16 ` [PATCH v6 6/6] keys: kill task_struct->replacement_session_keyring Oleg Nesterov
2012-04-20 8:45 ` David Howells
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