From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: Scott Wood <swood@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Juri Lelli <juri.lelli@redhat.com>,
Clark Williams <williams@redhat.com>,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH RT 4/4] rcutorture: Avoid problematic critical section nesting
Date: Thu, 27 Jun 2019 11:00:07 -0700 [thread overview]
Message-ID: <20190627180007.GA27126@linux.ibm.com> (raw)
In-Reply-To: <8462f30720637ec0da377aa737d26d2cad424d36.camel@redhat.com>
On Wed, Jun 26, 2019 at 11:49:16AM -0500, Scott Wood wrote:
> On Wed, 2019-06-26 at 11:08 -0400, Steven Rostedt wrote:
> > On Fri, 21 Jun 2019 16:59:55 -0700
> > "Paul E. McKenney" <paulmck@linux.ibm.com> wrote:
> >
> > > I have no objection to the outlawing of a number of these sequences in
> > > mainline, but am rather pointing out that until they really are outlawed
> > > and eliminated, rcutorture must continue to test them in mainline.
> > > Of course, an rcutorture running in -rt should avoid testing things that
> > > break -rt, including these sequences.
> >
> > We should update lockdep to complain about these sequences. That would
> > "outlaw" them in mainline. That is, after we clean up all the current
> > sequences in the code. And we also need to get Linus's approval of this
> > as I believe he was against enforcing this in the past.
>
> Was the opposition to prohibiting some specific sequence? It's only certain
> misnesting scenarios that are problematic. The rcu_read_lock/
> local_irq_disable restriction can be dropped with the IPI-to-self added in
> Paul's tree. Are there any known instances of the other two (besides
> rcutorture)?
Given the failure scenario Sebastian Siewior reported today, there
apparently are some, at least when running threaded interrupt handlers.
Thanx, Paul
next prev parent reply other threads:[~2019-06-27 18:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 1:19 [PATCH RT 0/4] Address rcutorture issues Scott Wood
2019-06-19 1:19 ` [PATCH RT 1/4] rcu: Acquire RCU lock when disabling BHs Scott Wood
2019-06-20 20:53 ` Paul E. McKenney
2019-06-20 21:06 ` Scott Wood
2019-06-20 21:20 ` Paul E. McKenney
2019-06-20 21:38 ` Scott Wood
2019-06-20 22:16 ` Paul E. McKenney
2019-06-19 1:19 ` [PATCH RT 2/4] sched: migrate_enable: Use sleeping_lock to indicate involuntary sleep Scott Wood
2019-06-19 1:19 ` [RFC PATCH RT 3/4] rcu: unlock special: Treat irq and preempt disabled the same Scott Wood
2019-06-20 21:10 ` Paul E. McKenney
2019-06-20 21:59 ` Scott Wood
2019-06-20 22:25 ` Paul E. McKenney
2019-06-20 23:08 ` Scott Wood
2019-06-22 0:26 ` Paul E. McKenney
2019-06-22 19:13 ` Paul E. McKenney
2019-06-24 17:40 ` Scott Wood
2019-06-19 1:19 ` [RFC PATCH RT 4/4] rcutorture: Avoid problematic critical section nesting Scott Wood
2019-06-20 21:18 ` Paul E. McKenney
2019-06-20 21:43 ` Scott Wood
2019-06-21 16:38 ` Sebastian Andrzej Siewior
2019-06-21 23:59 ` Paul E. McKenney
2019-06-26 15:08 ` Steven Rostedt
2019-06-26 16:49 ` Scott Wood
2019-06-27 18:00 ` Paul E. McKenney [this message]
2019-06-27 20:16 ` Scott Wood
2019-06-27 20:50 ` Paul E. McKenney
2019-06-27 22:46 ` Scott Wood
2019-06-28 0:52 ` Paul E. McKenney
2019-06-28 19:37 ` Scott Wood
2019-06-28 20:24 ` Paul E. McKenney
2019-06-20 19:12 ` [PATCH RT 0/4] Address rcutorture issues Paul E. McKenney
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