public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: "Serge E. Hallyn" <serge.hallyn@ubuntu.com>
To: Tejun Heo <tj@kernel.org>
Cc: Jeremiah Mahler <jmmahler@gmail.com>,
	cgroups@vger.kernel.org, Serge Hallyn <serge.hallyn@ubuntu.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	linux-kernel@vger.kernel.org,
	Dan Williams <dan.j.williams@intel.com>
Subject: Re: cgroup: BUG: unable to handle kernel NULL pointer dereference
Date: Sat, 2 Jan 2016 12:24:16 -0600	[thread overview]
Message-ID: <20160102182416.GA3957@mail.hallyn.com> (raw)
In-Reply-To: <20160102115437.GE3660@htj.duckdns.org>

On Sat, Jan 02, 2016 at 06:54:37AM -0500, Tejun Heo wrote:
> On Fri, Jan 01, 2016 at 03:40:28PM -0800, Jeremiah Mahler wrote:
> > all,
> > 
> > When running the latest linux-next (20151231) two of my machines
> > hang early in the boot sequence.  The initial message is for a
> > NULL pointer dereference.
> > 
> >   BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
> > 
> > And the RIP line refers to cgroup_path.
> > 
> >   RIP [<ffffffff810eb178>] cgroup_path+0x30/0x80
> > 
> > Attached are pictures of the back trace.
> > 
> > Let me know if I can do anything else to help.  I will investigate the
> > problem further if I get a chance.
> 
> This is most likely from the recent changes from cgroup ns support.
> Reverted the patchset for now as it also introduced a bisectability
> issue.  Serge, can you please look into this one?

Tried to reproduce with setting CONFIG_CFQ_GROUP_IOSCHED=y, but did not
succeed.  Could you send me the .config?  Also, if someone could send
the objdump -d output that might help.  Though really, it seems clear
that current->nsproxy must be NULL.  Hm, that's right -  we used to have
that issue in pidns (or was it netns) during process exit.  I don't know
that I'll get time this afternoon, but I'll look into it asap.

thanks.

  reply	other threads:[~2016-01-02 18:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160101234028.GA1750@hudson.localdomain>
2016-01-02 11:54 ` cgroup: BUG: unable to handle kernel NULL pointer dereference Tejun Heo
2016-01-02 18:24   ` Serge E. Hallyn [this message]
2016-01-02 21:50     ` Jeremiah Mahler
2016-01-03  0:59       ` Serge E. Hallyn
2016-01-03  3:41         ` Serge E. Hallyn
2016-01-04 19:15   ` Serge E. Hallyn
2016-01-04 19:17     ` Tejun Heo

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=20160102182416.GA3957@mail.hallyn.com \
    --to=serge.hallyn@ubuntu.com \
    --cc=cgroups@vger.kernel.org \
    --cc=dan.j.williams@intel.com \
    --cc=jmmahler@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sfr@canb.auug.org.au \
    --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