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From: Joel Fernandes <joel@joelfernandes.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	"Paul E. McKenney" <paulmck@linux.ibm.com>,
	rcu <rcu@vger.kernel.org>, LKML <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 13:46:27 -0400	[thread overview]
Message-ID: <CAEXW_YTmx3wFKuiLyrQO6uSPYAL179EPa6N3WO7qZahccCs-pg@mail.gmail.com> (raw)
In-Reply-To: <CAEXW_YTvkSTqwi_jOE2Pr+uD-GC4Xv0CtBEL9YO7=LvJcM3FBQ@mail.gmail.com>

On Thu, Jun 27, 2019 at 1:43 PM Joel Fernandes <joel@joelfernandes.org> wrote:
>
> On Thu, Jun 27, 2019 at 11:40 AM Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
> >
> > On 2019-06-27 11:37:10 [-0400], Joel Fernandes wrote:
> > > Sebastian it would be nice if possible to trace where the
> > > t->rcu_read_unlock_special is set for this scenario of calling
> > > rcu_read_unlock_special, to give a clear idea about whether it was
> > > really because of an IPI. I guess we could also add additional RCU
> > > debug fields to task_struct (just for debugging) to see where there
> > > unlock_special is set.
> > >
> > > Is there a test to reproduce this, or do I just boot an intel x86_64
> > > machine with "threadirqs" and run into it?
> >
> > Do you want to send me a patch or should I send you my kvm image which
> > triggers the bug on boot?
>
> I could reproduce this as well just booting Linus tree with threadirqs
> command line and running rcutorture. In 15 seconds or so it locks
> up... gdb backtrace shows the recursive lock:

Sorry that got badly wrapped, so I pasted it here:
https://hastebin.com/ajivofomik.shell

  reply	other threads:[~2019-06-27 17:46 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
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 [this message]
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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