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Subject: [RFC/RFT PATCH v3] sched: automated per tty task groups
From: Mike Galbraith <efault@gmx.de>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Ingo Molnar <mingo@elte.hu>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Markus Trippelsdorf <markus@trippelsdorf.de>
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Date: Tue, 26 Oct 2010 09:07:18 +0200
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On Thu, 2010-10-21 at 18:29 +0200, Oleg Nesterov wrote:

> It is not clear to me why do we need rcu_read_lock() and how it can help.
> The tty can go away right after dereferencing signal->tty.

Which was Marcus' crash.  Didn't happen here only because I didn't have
CONFIG_PREEMPT set.

Changes since v2:
  - drop