From: Jan Kara <jack@suse.cz>
To: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>, Jan Kara <jack@suse.cz>,
axboe@kernel.dk, yuyufen@huawei.com, tj@kernel.org,
tytso@mit.edu, gregkh@linuxfoundation.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] bdi: add a ->dev_name field to struct backing_dev_info
Date: Mon, 20 Apr 2020 11:52:18 +0200 [thread overview]
Message-ID: <20200420095218.GB17130@quack2.suse.cz> (raw)
In-Reply-To: <20200420074801.GA30795@lst.de>
On Mon 20-04-20 09:48:01, Christoph Hellwig wrote:
> On Sun, Apr 19, 2020 at 06:06:51PM +0200, Christoph Hellwig wrote:
> > > (https://lore.kernel.org/linux-block/20200416071519.807660-4-hch@lst.de/)
> > > and also to the replies to that patch? This is what I found in the replies:
> > > "When driver try to to re-register bdi but without release_bdi(), the old
> > > dev_name will be cover directly by the newer in bdi_register_va(). So, I am
> > > not sure whether it can cause memory leak for bdi->dev_name."
> > >
> > > Has it been considered to avoid that leak by freeing bdi->dev_name from
> > > unregister_bdi(), e.g. as follows?
> >
> > We'd need some protection against concurrent accesses as unregister_bdi
> > can race with them. But with RCU that could be handled, so let me try
> > that.
>
> I looked into it, and while it seems doable I think this goes in the
> wrong direction as it pushed the RCU knowledge into the callers. I'd
> rather get something like this series in ASAP, and then for 5.8 or 5.9
> move the bdi pointer to the gendisk and stop re-registering it and thus
> solve the problems root cause for real.
Yeah, if it could be done it would be a nice solution. Because
re-registering of BDIs is a long-term source of troubles...
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-04-20 9:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-16 16:54 bdi: fix use-after-free for dev_name(bdi->dev) v2 Christoph Hellwig
2020-04-16 16:54 ` [PATCH 1/8] bdi: move bdi_dev_name out of line Christoph Hellwig
2020-04-18 15:35 ` Bart Van Assche
2020-04-16 16:54 ` [PATCH 2/8] bdi: use bdi_dev_name() to get device name Christoph Hellwig
2020-04-18 15:37 ` Bart Van Assche
2020-04-16 16:54 ` [PATCH 3/8] bdi: add a ->dev_name field to struct backing_dev_info Christoph Hellwig
2020-04-17 8:59 ` Jan Kara
2020-04-17 13:01 ` Christoph Hellwig
2020-04-20 11:41 ` Hans de Goede
2020-04-20 11:58 ` Christoph Hellwig
2020-04-21 12:42 ` Hans de Goede
2020-04-18 15:40 ` Bart Van Assche
2020-04-19 7:58 ` Christoph Hellwig
2020-04-19 15:29 ` Bart Van Assche
2020-04-19 16:06 ` Christoph Hellwig
2020-04-20 7:48 ` Christoph Hellwig
2020-04-20 9:52 ` Jan Kara [this message]
2020-04-20 9:49 ` Jan Kara
2020-04-16 16:54 ` [PATCH 4/8] driver core: remove device_create_vargs Christoph Hellwig
2020-04-16 16:54 ` [PATCH 5/8] bdi: unexport bdi_register_va Christoph Hellwig
2020-04-18 15:41 ` Bart Van Assche
2020-04-16 16:54 ` [PATCH 6/8] bdi: remove bdi_register_owner Christoph Hellwig
2020-04-18 15:43 ` Bart Van Assche
2020-04-16 16:54 ` [PATCH 7/8] bdi: simplify bdi_alloc Christoph Hellwig
2020-04-18 15:44 ` Bart Van Assche
2020-04-16 16:54 ` [PATCH 8/8] bdi: remove the name field in struct backing_dev_info Christoph Hellwig
2020-04-18 15:45 ` Bart Van Assche
-- strict thread matches above, loose matches on Subject: below --
2020-04-16 7:15 bdi: fix use-after-free for dev_name(bdi->dev) Christoph Hellwig
2020-04-16 7:15 ` [PATCH 3/8] bdi: add a ->dev_name field to struct backing_dev_info Christoph Hellwig
2020-04-16 7:52 ` Greg KH
2020-04-16 8:34 ` Yufen Yu
2020-04-16 12:02 ` Jan Kara
2020-04-16 12:19 ` Christoph Hellwig
2020-04-16 12:22 ` Christoph Hellwig
2020-04-16 12:31 ` 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=20200420095218.GB17130@quack2.suse.cz \
--to=jack@suse.cz \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=gregkh@linuxfoundation.org \
--cc=hch@lst.de \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tj@kernel.org \
--cc=tytso@mit.edu \
--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).