From: Peter Zijlstra <peterz@infradead.org>
To: Rik van Riel <riel@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] signal: simplify deadlock-avoidance in lock_task_sighand()
Date: Tue, 23 Sep 2014 16:20:37 +0200 [thread overview]
Message-ID: <20140923142037.GG3312@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <54215D52.8030201@redhat.com>
On Tue, Sep 23, 2014 at 07:45:22AM -0400, Rik van Riel wrote:
> > I really thing the preempt_disable/enable is not needed.
> >
> > Paul, Thomas, care to comment?
>
> I suspect you are right. On normal kernels, rcu_read_lock() will
> ensure preemption is disabled.
>
> On -rt, the locks within are all sleepable mutexes.
>
> Either way, things should be ok.
But with CONFIG_PREEMPT we get preemptible RCU but not the
spinlock->rt_mutex conversion.
next prev parent reply other threads:[~2014-09-23 14:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-22 16:44 [PATCH 0/2] signal: simplify/document lock_task_sighand() logic Oleg Nesterov
2014-09-22 16:44 ` [PATCH 1/2] signal: simplify deadlock-avoidance in lock_task_sighand() Oleg Nesterov
2014-09-22 18:58 ` Steven Rostedt
2014-09-22 19:11 ` Oleg Nesterov
2014-09-22 21:24 ` Steven Rostedt
2014-09-23 11:45 ` Rik van Riel
2014-09-23 14:20 ` Peter Zijlstra [this message]
2014-09-23 14:30 ` Steven Rostedt
2014-09-23 19:03 ` Oleg Nesterov
2014-09-24 8:36 ` Paul E. McKenney
2014-09-23 15:55 ` Peter Zijlstra
2014-09-22 16:44 ` [PATCH 2/2] signal: document the RCU protection of ->sighand Oleg Nesterov
2014-09-22 19:00 ` Steven Rostedt
2014-09-23 11:50 ` Rik van Riel
2014-09-28 21:43 ` [PATCH v2 0/2] document ->sighand protection, rcu_read_unlock() deadlocks Oleg Nesterov
2014-09-28 21:44 ` [PATCH v2 1/2] signal: document the RCU protection of ->sighand Oleg Nesterov
2014-09-28 21:44 ` [PATCH v2 2/2] rcu: more info about potential deadlocks with rcu_read_unlock() Oleg Nesterov
2014-10-23 19:56 ` [PATCH v2 0/2] document ->sighand protection, rcu_read_unlock() deadlocks Oleg Nesterov
2014-10-23 20:29 ` Paul E. McKenney
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