From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>,
mingo@kernel.org, "Rafael J. Wysocki" <rafael@kernel.org>,
Tejun Heo <tj@kernel.org>,
linux hotplug mailing <linux-hotplug@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>
Subject: Re: Possible deadlock related to CPU hotplug and kernfs
Date: Tue, 08 Sep 2015 22:28:12 +0000 [thread overview]
Message-ID: <4305045.rOCzS8rSge@vostro.rjw.lan> (raw)
In-Reply-To: <20150908104008.GD3644@twins.programming.kicks-ass.net>
On Tuesday, September 08, 2015 12:40:08 PM Peter Zijlstra wrote:
> On Mon, Sep 07, 2015 at 11:33:21PM +0200, Rafael J. Wysocki wrote:
> > On Monday, September 07, 2015 11:11:19 AM Jiang Liu wrote:
> > Peter, Ingo, some help from lockdep expert is needed.
> >
> > We have a splat that almost certainly is a false positive (the original report
> > is here http://marc.info/?l=linux-kernel&m\x144109156901959&w=4) and no ideas
> > how to make it go away. Can you please have a look and advise?
>
> I can't even find the relevant code :/
>
> From that email I get kernfs_fop_write() which calls
> kernfs_get_active(), but that does _NOT_ call cpu_up(), so that
> callchain is shite.
>
> The actual lockdep splat is also not really helpful, and is spraying
> names over: acpi, device, sysfs and kernfs (do we really need that many
> layeres of obfuscation for a simple file?)
>
> So, please, start by explaining the thing proper such that simple people
> like me know what to look for.
OK, I'll try to get that later this week.
Or maybe Jiang Liu can beat me to doing that. :-)
Thanks,
Rafael
prev parent reply other threads:[~2015-09-08 22:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-01 7:12 Possible deadlock related to CPU hotplug and kernfs Jiang Liu
2015-09-02 16:14 ` Tejun Heo
2015-09-03 0:58 ` Rafael J. Wysocki
2015-09-03 16:19 ` Tejun Heo
2015-09-03 20:08 ` Rafael J. Wysocki
2015-09-04 7:20 ` Jiang Liu
2015-09-04 14:16 ` Rafael J. Wysocki
2015-09-07 3:11 ` Jiang Liu
2015-09-07 21:33 ` Rafael J. Wysocki
2015-09-08 10:40 ` Peter Zijlstra
2015-09-08 22:28 ` Rafael J. Wysocki [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=4305045.rOCzS8rSge@vostro.rjw.lan \
--to=rjw@rjwysocki.net \
--cc=jiang.liu@linux.intel.com \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-hotplug@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=rafael@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 read-only IMAP folder(s) and NNTP newsgroup(s).