From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Tejun Heo <tj@kernel.org>
Cc: jiangshanlai@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: WARN_ON_ONCE() in process_one_work()?
Date: Sat, 17 Jun 2017 10:31:05 -0700 [thread overview]
Message-ID: <20170617173105.GI3721@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170617115314.GA20758@htj.duckdns.org>
On Sat, Jun 17, 2017 at 07:53:14AM -0400, Tejun Heo wrote:
> Hello,
>
> On Fri, Jun 16, 2017 at 10:36:58AM -0700, Paul E. McKenney wrote:
> > And no test failures from yesterday evening. So it looks like we get
> > somewhere on the order of one failure per 138 hours of TREE07 rcutorture
> > runtime with your printk() in the mix.
> >
> > Was the above output from your printk() output of any help?
>
> Yeah, if my suspicion is correct, it'd require new kworker creation
> racing against CPU offline, which would explain why it's so difficult
> to repro. Can you please see whether the following patch resolves the
> issue?
That could explain why only Steve Rostedt and I saw the issue. As far
as I know, we are the only ones who regularly run CPU-hotplug stress
tests. ;-)
I have a weekend-long run going, but will give this a shot overnight on
Monday, Pacific Time. Thank you for putting it together, looking forward
to seeing what it does!
Thanx, Paul
> Thanks.
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 803c3bc274c4..1500217ce4b4 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -980,8 +980,13 @@ struct migration_arg {
> static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
> struct task_struct *p, int dest_cpu)
> {
> - if (unlikely(!cpu_active(dest_cpu)))
> - return rq;
> + if (p->flags & PF_KTHREAD) {
> + if (unlikely(!cpu_online(dest_cpu)))
> + return rq;
> + } else {
> + if (unlikely(!cpu_active(dest_cpu)))
> + return rq;
> + }
>
> /* Affinity changed (again). */
> if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
>
next prev parent reply other threads:[~2017-06-17 17:31 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-01 16:57 WARN_ON_ONCE() in process_one_work()? Paul E. McKenney
2017-05-01 18:38 ` Paul E. McKenney
2017-05-01 18:44 ` Tejun Heo
2017-05-01 18:58 ` Paul E. McKenney
2017-05-05 17:11 ` Paul E. McKenney
2017-06-13 20:58 ` Tejun Heo
2017-06-13 22:31 ` Paul E. McKenney
2017-06-14 15:15 ` Paul E. McKenney
2017-06-15 15:38 ` Paul E. McKenney
2017-06-16 17:36 ` Paul E. McKenney
2017-06-17 11:53 ` Tejun Heo
2017-06-17 17:31 ` Paul E. McKenney [this message]
2017-06-18 10:40 ` Tejun Heo
2017-06-20 16:45 ` Paul E. McKenney
2017-06-21 15:30 ` Paul E. McKenney
2017-06-23 16:41 ` Paul E. McKenney
2017-06-27 16:27 ` Paul E. McKenney
2017-05-01 18:42 ` Tejun Heo
2017-05-01 19:42 ` Steven Rostedt
2017-05-01 19:50 ` Tejun Heo
2017-05-01 20:02 ` Steven Rostedt
2018-06-20 19:29 Paul E. McKenney
2018-07-02 21:05 ` Tejun Heo
2018-07-03 4:05 ` Paul E. McKenney
2018-07-03 16:40 ` Paul E. McKenney
2018-07-03 20:12 ` Tejun Heo
2018-07-03 21:44 ` Paul E. McKenney
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170617173105.GI3721@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=jiangshanlai@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).