From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
linux-kernel@vger.kernel.org
Subject: Re: RCU lockup in the SMP idle thread, help...
Date: Thu, 20 Sep 2012 07:10:52 -0700 [thread overview]
Message-ID: <20120920141052.GA2449@linux.vnet.ibm.com> (raw)
In-Reply-To: <CACRpkdaufGjsEtkjQFY9oDvmtM7xnEiFweLfOGuX+WRf0Vbb5A@mail.gmail.com>
On Thu, Sep 20, 2012 at 11:07:37AM +0200, Linus Walleij wrote:
> On Thu, Sep 20, 2012 at 2:03 AM, Paul E. McKenney
> <paulmck@linux.vnet.ibm.com> wrote:
>
> > In the meantime, a crude fallback is for the CPU that detected the stall
> > to trace the stack of the task running on the other CPU. See below for
> > a crude (and untested) patch.
>
> OK now I get this:
>
> INFO: rcu_preempt detected stalls on CPUs/tasks: { 0} (detected by 1,
> t=29508 jiffies)
> Task dump for CPU 0:
> swapper/0 R running 0 0 0 0x00000000
> [<c02da614>] (__schedule+0x238/0x52c) from [<c000f238>] (default_idle+0x28/0x30)
> [<c000f238>] (default_idle+0x28/0x30) from [<ffffffff>] (0xffffffff)
> INFO: rcu_preempt detected stalls on CPUs/tasks: { 0} (detected by 1,
> t=29851 jiffies)
> Task dump for CPU 0:
> swapper/0 R running 0 0 0 0x00000000
> [<c02da614>] (__schedule+0x238/0x52c) from [<c000f238>] (default_idle+0x28/0x30)
> [<c000f238>] (default_idle+0x28/0x30) from [<ffffffff>] (0xffffffff)
>
> So the swapper thread is the culprit?
> Hm, I'm not very smart with this no...
Can we convince ARM to dump the stack of the swapper thread in this case?
That would get us valuable information.
Thanx, Paul
prev parent reply other threads:[~2012-09-20 14:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-13 12:36 RCU lockup in the SMP idle thread, help Linus Walleij
2012-09-13 16:49 ` John Stultz
2012-09-13 16:58 ` Paul E. McKenney
2012-09-14 7:27 ` Linus Walleij
2012-09-14 17:53 ` Paul E. McKenney
2012-09-17 9:10 ` Linus Walleij
2012-09-20 0:03 ` Paul E. McKenney
2012-09-20 8:46 ` Linus Walleij
2012-09-20 17:49 ` Nicolas Pitre
2012-09-20 9:07 ` Linus Walleij
2012-09-20 14:10 ` Paul E. McKenney [this message]
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=20120920141052.GA2449@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=daniel.lezcano@linaro.org \
--cc=john.stultz@linaro.org \
--cc=linus.walleij@linaro.org \
--cc=linux-kernel@vger.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