From: Steven Rostedt <rostedt@goodmis.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Josh Triplett <josh@joshtriplett.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>
Subject: Re: [RFC] Deadlock via recursive wakeup via RCU with threadirqs
Date: Thu, 27 Jun 2019 10:34:55 -0400 [thread overview]
Message-ID: <20190627103455.01014276@gandalf.local.home> (raw)
In-Reply-To: <20190627142436.GD215968@google.com>
On Thu, 27 Jun 2019 10:24:36 -0400
Joel Fernandes <joel@joelfernandes.org> wrote:
> > What am I missing here?
>
> This issue I think is
>
> (in normal process context)
> spin_lock_irqsave(rq_lock); // which disables both preemption and interrupt
> // but this was done in normal process context,
> // not from IRQ handler
> rcu_read_lock();
> <---------- IPI comes in and sets exp_hint
How would an IPI come in here with interrupts disabled?
-- Steve
> rcu_read_unlock()
> -> rcu_read_unlock_special
> -> raise_softirq_irqoff
> -> wakeup_softirq <--- because in_interrupt returns false.
>
> I think the issue is in_interrupt() does not know about threaded interrupts.
> If it did, then the ksoftirqd wake up would not happen.
>
> Did I get something wrong?
next prev parent reply other threads:[~2019-06-27 14:35 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-26 13:54 [RFC] Deadlock via recursive wakeup via RCU with threadirqs Sebastian Andrzej Siewior
2019-06-26 16:25 ` Paul E. McKenney
2019-06-27 7:47 ` Sebastian Andrzej Siewior
2019-06-27 15:52 ` Paul E. McKenney
2019-06-27 14:24 ` Joel Fernandes
2019-06-27 14:34 ` Steven Rostedt [this message]
2019-06-27 15:30 ` Joel Fernandes
2019-06-27 15:37 ` Joel Fernandes
2019-06-27 15:40 ` Sebastian Andrzej Siewior
2019-06-27 15:42 ` Joel Fernandes
2019-06-27 17:43 ` Joel Fernandes
2019-06-27 17:46 ` Joel Fernandes
2019-06-27 18:11 ` Paul E. McKenney
2019-06-27 18:27 ` Joel Fernandes
2019-06-27 18:51 ` Joel Fernandes
2019-06-27 19:14 ` Paul E. McKenney
2019-06-27 19:15 ` Paul E. McKenney
2019-06-27 18:30 ` Paul E. McKenney
2019-06-27 20:45 ` Paul E. McKenney
2019-06-27 15:55 ` Paul E. McKenney
2019-06-27 16:47 ` Joel Fernandes
2019-06-27 17:38 ` Paul E. McKenney
2019-06-27 18:16 ` Joel Fernandes
2019-06-27 18:41 ` Paul E. McKenney
2019-06-27 20:17 ` Scott Wood
2019-06-27 20:36 ` Paul E. McKenney
2019-06-28 7:31 ` Byungchul Park
2019-06-28 7:43 ` Byungchul Park
2019-06-28 8:14 ` Byungchul Park
2019-06-28 8:24 ` Byungchul Park
2019-06-28 12:24 ` Paul E. McKenney
2019-06-28 9:10 ` Byungchul Park
2019-06-28 9:28 ` Byungchul Park
2019-06-28 12:21 ` Paul E. McKenney
2019-06-28 10:40 ` Byungchul Park
2019-06-28 12:27 ` Paul E. McKenney
2019-06-28 15:44 ` Steven Rostedt
2019-06-29 15:12 ` Andrea Parri
2019-06-29 16:55 ` Paul E. McKenney
2019-06-29 18:09 ` Andrea Parri
2019-06-29 18:21 ` Andrea Parri
2019-06-29 19:15 ` Paul E. McKenney
2019-06-29 19:35 ` Andrea Parri
2019-06-30 23:55 ` Byungchul Park
2019-06-28 14:15 ` Peter Zijlstra
2019-06-28 15:54 ` Paul E. McKenney
2019-06-28 16:04 ` Peter Zijlstra
2019-06-28 17:20 ` Paul E. McKenney
2019-07-01 9:42 ` Peter Zijlstra
2019-07-01 10:24 ` Sebastian Andrzej Siewior
2019-07-01 12:23 ` Paul E. McKenney
2019-07-01 14:00 ` Peter Zijlstra
2019-07-01 16:01 ` Paul E. McKenney
2019-06-28 20:01 ` Scott Wood
2019-07-01 9:45 ` Peter Zijlstra
2019-06-28 13:54 ` Peter Zijlstra
2019-06-28 15:30 ` Paul E. McKenney
2019-06-28 18:40 ` Sebastian Andrzej Siewior
2019-06-28 18:52 ` Paul E. McKenney
2019-06-28 19:24 ` Joel Fernandes
2019-06-28 20:04 ` Paul E. McKenney
2019-06-28 21:40 ` Joel Fernandes
2019-06-28 22:25 ` Paul E. McKenney
2019-06-28 23:12 ` Joel Fernandes
2019-06-29 0:06 ` Paul E. McKenney
2019-06-28 16:40 ` Joel Fernandes
2019-06-28 16:45 ` Joel Fernandes
2019-06-28 17:30 ` Paul E. McKenney
2019-06-28 17:41 ` Paul E. McKenney
2019-06-28 17:45 ` Sebastian Andrzej Siewior
2019-06-28 18:07 ` Joel Fernandes
2019-06-28 18:20 ` Sebastian Andrzej Siewior
2019-07-01 2:08 ` Joel Fernandes
2019-06-28 18:22 ` Paul E. McKenney
2019-06-28 19:29 ` Joel Fernandes
2019-06-28 20:06 ` Paul E. McKenney
2019-06-28 18:05 ` Joel Fernandes
2019-06-28 18:23 ` Paul E. McKenney
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