From: Tejun Heo <tj@kernel.org>
To: Yufen Yu <yuyufen@huawei.com>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org, jack@suse.cz,
bvanassche@acm.org
Subject: Re: [PATCH] bdi: fix use-after-free for bdi device
Date: Wed, 12 Feb 2020 22:48:18 -0500 [thread overview]
Message-ID: <20200213034818.GE88887@mtj.thefacebook.com> (raw)
In-Reply-To: <fd9d78b9-1119-27cc-fa74-04cb85d4f578@huawei.com>
Hello,
On Thu, Feb 13, 2020 at 10:46:34AM +0800, Yufen Yu wrote:
> For each time of register, bdi_register() will try to create a new 'dev'.
>
> bdi_register
> bdi_register_va
> if (bdi->dev) // if bdi->dev is not NULL, return directly
> return 0;
> dev = device_create_vargs()...
>
> So, I think freeing bdi->dev until bdi itself does may be a problem
> for drivers that supported re-registration bdi, such as:
Ugh, thanks for noticing that. I guess the right thing to do is then
going full RCU. What do you think about expanding your previous patch
so that ->dev has __rcu annotation, users use the RCU accessors and
the device is destroyed asynchronously through call_rcu()?
Thanks.
--
tejun
next prev parent reply other threads:[~2020-02-13 3:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 14:00 [PATCH] bdi: fix use-after-free for bdi device Yufen Yu
2020-02-11 13:57 ` Yufen Yu
2020-02-12 21:33 ` Tejun Heo
2020-02-13 2:46 ` Yufen Yu
2020-02-13 3:48 ` Tejun Heo [this message]
2020-02-13 7:51 ` Yufen Yu
2020-02-13 13:58 ` Tejun Heo
2020-02-14 2:50 ` Yufen Yu
2020-02-14 14:05 ` Tejun Heo
2020-02-15 13:54 ` Yufen Yu
2020-02-19 12:55 ` Jan Kara
2020-02-19 15:12 ` Tejun Heo
2020-02-20 11:07 ` Yufen Yu
2020-02-20 12:07 ` Jan Kara
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=20200213034818.GE88887@mtj.thefacebook.com \
--to=tj@kernel.org \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=jack@suse.cz \
--cc=linux-block@vger.kernel.org \
--cc=yuyufen@huawei.com \
/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).