From: Tejun Heo <tj@kernel.org>
To: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Rabin Vincent <rabin@rab.in>, Jens Axboe <axboe@fb.com>,
Jan Kara <jack@suse.cz>, Al Viro <viro@zeniv.linux.org.uk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] bdev: fix NULL pointer dereference in sync()/close() race
Date: Mon, 29 Aug 2016 16:54:39 -0400 [thread overview]
Message-ID: <20160829205439.GG28713@mtj.duckdns.org> (raw)
In-Reply-To: <5c8ff17a-27ba-0987-401d-9eeeb66b52f2@oracle.com>
Hello,
On Mon, Aug 29, 2016 at 10:49:57PM +0200, Vegard Nossum wrote:
> That didn't work at all. I guess bd_acquire() would just do a bdgrab()
> and not touch ->bd_holders, whereas blkdev_get() would increment
Yeah, bdev has two different refs - one for bdev struct itself and the
other for the actual accessors.
> bd_holders and therefore prevent __blkdev_put() from freeing the block
> device? Too confusing...
I think you'll need to do the actual blkdev_get or one of its
variants.
Thanks.
--
tejun
next prev parent reply other threads:[~2016-08-29 20:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-27 7:07 [PATCH] bdev: fix NULL pointer dereference in sync()/close() race Vegard Nossum
2016-08-27 9:03 ` Rabin Vincent
2016-08-27 9:30 ` Vegard Nossum
2016-08-29 19:55 ` Tejun Heo
2016-08-29 20:49 ` Vegard Nossum
2016-08-29 20:54 ` Tejun Heo [this message]
2016-08-29 21:33 ` Vegard Nossum
2016-08-29 23:49 ` 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=20160829205439.GG28713@mtj.duckdns.org \
--to=tj@kernel.org \
--cc=axboe@fb.com \
--cc=jack@suse.cz \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rabin@rab.in \
--cc=stable@vger.kernel.org \
--cc=vegard.nossum@oracle.com \
--cc=viro@zeniv.linux.org.uk \
/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).