From: Jens Axboe <axboe@kernel.dk>
To: Tejun Heo <tj@kernel.org>
Cc: Josh Boyer <jwboyer@fedoraproject.org>,
Jeff Moyer <jmoyer@redhat.com>,
msnitzer@redhat.com, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org,
"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
"Richard W.M. Jones" <rjones@redhat.com>
Subject: Re: [PATCH block/for-linus] block: blkg_destroy_all() should clear q->root_blkg and ->root_rl.blkg
Date: Tue, 8 Sep 2015 09:35:04 -0600 [thread overview]
Message-ID: <55EF0028.30203@kernel.dk> (raw)
In-Reply-To: <20150908153132.GD13749@mtj.duckdns.org>
On 09/08/2015 09:31 AM, Tejun Heo wrote:
> On Sat, Sep 05, 2015 at 03:47:36PM -0400, Tejun Heo wrote:
>> While making the root blkg unconditional, ec13b1d6f0a0 ("blkcg: always
>> create the blkcg_gq for the root blkcg") removed the part which clears
>> q->root_blkg and ->root_rl.blkg during q exit. This leaves the two
>> pointers dangling after blkg_destroy_all(). blk-throttle exit path
>> performs blkg traversals and dereferences ->root_blkg and can lead to
>> the following oops.
>
> Jens, can you please route this one w/ Richard's tested-by added?
Yup, added, thanks.
--
Jens Axboe
prev parent reply other threads:[~2015-09-08 15:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-30 12:30 __blkg_lookup oops with 4.2-rcX Josh Boyer
2015-08-30 18:04 ` Richard W.M. Jones
2015-09-02 14:53 ` Tejun Heo
[not found] ` <20150902145307.GG22326-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-09-02 15:32 ` Tejun Heo
2015-09-04 10:46 ` Richard W.M. Jones
[not found] ` <20150904104602.GN29283-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-09-04 17:13 ` Tejun Heo
[not found] ` <20150904171302.GE25329-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-09-04 18:17 ` Richard W.M. Jones
2015-09-04 20:42 ` Richard W.M. Jones
2015-09-05 15:34 ` Richard W.M. Jones
[not found] ` <20150905153439.GA18461-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-09-05 15:48 ` Richard W.M. Jones
[not found] ` <20150905154840.GA19460-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-09-05 18:38 ` Tejun Heo
[not found] ` <20150905183801.GA8231-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-09-05 19:47 ` [PATCH block/for-linus] block: blkg_destroy_all() should clear q->root_blkg and ->root_rl.blkg Tejun Heo
2015-09-06 8:30 ` Richard W.M. Jones
[not found] ` <20150905194736.GB8231-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-09-08 15:31 ` Tejun Heo
2015-09-08 15:35 ` Jens Axboe [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=55EF0028.30203@kernel.dk \
--to=axboe@kernel.dk \
--cc=cgroups@vger.kernel.org \
--cc=hannes@cmpxchg.org \
--cc=jmoyer@redhat.com \
--cc=jwboyer@fedoraproject.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan@huawei.com \
--cc=msnitzer@redhat.com \
--cc=rjones@redhat.com \
--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).