From: Luis Chamberlain <mcgrof@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org,
rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz,
nstange@suse.de, akpm@linux-foundation.org, mhocko@suse.com,
yukuai3@huawei.com, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Omar Sandoval <osandov@fb.com>,
Hannes Reinecke <hare@suse.com>, Michal Hocko <mhocko@kernel.org>,
syzbot+603294af2d01acfdd6da@syzkaller.appspotmail.com
Subject: Re: [PATCH v2 03/10] blktrace: fix debugfs use after free
Date: Fri, 24 Apr 2020 23:47:41 +0000 [thread overview]
Message-ID: <20200424234741.GE11244@42.do-not-panic.com> (raw)
In-Reply-To: <20200422094320.GH299948@T590>
On Wed, Apr 22, 2020 at 05:43:20PM +0800, Ming Lei wrote:
> On Wed, Apr 22, 2020 at 07:28:59AM +0000, Luis Chamberlain wrote:
> > At this point in time patch-wise we still haven't reverted back to
> > synchronous request_queue removal. Considering this, a race with the
> > parent disappearing can happen because the request_queue removal is
> > deferred, that is, the request_queue's kobject's release() call used
> > schedule_work() to finish off its removal. We expect the last
> > blk_put_queue() to be called at the end of blk_cleanup_queue(). Since
>
> Actually no, we expect that request queue is released after disk is
> released. Don't forget that gendisk does hold one extra refcount of
> request queue.
Then by all means using blk_put_queue() from everywhere should be safe
in atomic context, as we have control over that blk_put_queue() on the
block layer.
(Modulo, we accept the races possible today on blk_get_queue(), which
I'll try to address).
Luis
next prev parent reply other threads:[~2020-04-24 23:47 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-19 19:45 [PATCH v2 00/10] block: fix blktrace debugfs use after free Luis Chamberlain
2020-04-19 19:45 ` [PATCH v2 01/10] block: move main block debugfs initialization to its own file Luis Chamberlain
2020-04-19 21:06 ` Bart Van Assche
2020-04-19 19:45 ` [PATCH v2 02/10] blktrace: move blktrace debugfs creation to helper function Luis Chamberlain
2020-04-19 21:11 ` Bart Van Assche
2020-04-22 7:12 ` Christoph Hellwig
2020-04-19 19:45 ` [PATCH v2 03/10] blktrace: fix debugfs use after free Luis Chamberlain
2020-04-19 21:55 ` Bart Van Assche
2020-04-20 0:04 ` Luis Chamberlain
2020-04-20 0:38 ` Bart Van Assche
2020-04-20 18:46 ` Luis Chamberlain
2020-04-20 20:16 ` Greg KH
2020-04-20 20:41 ` Luis Chamberlain
2020-04-21 7:00 ` Greg KH
2020-04-22 7:28 ` Luis Chamberlain
2020-04-22 9:43 ` Ming Lei
2020-04-22 10:31 ` Luis Chamberlain
2020-04-24 23:47 ` Luis Chamberlain [this message]
2020-04-22 7:29 ` Christoph Hellwig
2020-04-22 7:34 ` Luis Chamberlain
2020-04-22 7:27 ` Christoph Hellwig
2020-04-22 7:48 ` Luis Chamberlain
2020-04-22 8:10 ` Christoph Hellwig
2020-04-22 8:26 ` Luis Chamberlain
2020-04-19 19:45 ` [PATCH v2 04/10] block: revert back to synchronous request_queue removal Luis Chamberlain
2020-04-19 22:23 ` Bart Van Assche
2020-04-20 18:59 ` Luis Chamberlain
2020-04-20 21:11 ` Bart Van Assche
2020-04-20 21:51 ` Luis Chamberlain
2020-04-19 19:45 ` [PATCH v2 05/10] blktrace: upgrade warns to BUG_ON() on unexpected circmunstances Luis Chamberlain
2020-04-19 22:50 ` Bart Van Assche
2020-04-19 23:07 ` Luis Chamberlain
2020-04-20 23:20 ` Steven Rostedt
2020-04-19 19:45 ` [PATCH v2 06/10] blk-debugfs: upgrade warns to BUG_ON() if directory is already found Luis Chamberlain
2020-04-20 11:36 ` Greg KH
2020-04-19 19:45 ` [PATCH v2 07/10] blktrace: move debugfs file creation to its own function Luis Chamberlain
2020-04-19 22:55 ` Bart Van Assche
2020-04-20 11:37 ` Greg KH
2020-04-19 19:45 ` [PATCH v2 08/10] blktrace: add checks for created debugfs files on setup Luis Chamberlain
2020-04-19 22:57 ` Bart Van Assche
2020-04-19 23:05 ` Luis Chamberlain
2020-04-19 23:17 ` Bart Van Assche
2020-04-20 11:40 ` Greg KH
2020-04-20 18:44 ` Luis Chamberlain
2020-04-20 20:11 ` Greg KH
2020-04-20 20:20 ` Luis Chamberlain
2020-04-21 6:55 ` Greg KH
2020-04-20 11:39 ` Greg KH
2020-04-19 19:45 ` [PATCH v2 09/10] block: panic if block debugfs dir is not created Luis Chamberlain
2020-04-19 23:08 ` Bart Van Assche
2020-04-20 11:38 ` Greg KH
2020-04-19 19:45 ` [PATCH v2 10/10] block: put_device() if device_add() fails Luis Chamberlain
2020-04-19 23:40 ` Bart Van Assche
2020-04-24 22:32 ` Luis Chamberlain
2020-04-25 1:58 ` Bart Van Assche
2020-04-25 2:12 ` Luis Chamberlain
2020-04-19 19:48 ` [PATCH v2 00/10] block: fix blktrace debugfs use after free Luis Chamberlain
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