From: Bart Van Assche <bvanassche@acm.org>
To: Luis Chamberlain <mcgrof@kernel.org>,
axboe@kernel.dk, viro@zeniv.linux.org.uk,
gregkh@linuxfoundation.org, rostedt@goodmis.org,
mingo@redhat.com, jack@suse.cz, ming.lei@redhat.com,
nstange@suse.de, akpm@linux-foundation.org
Cc: mhocko@suse.com, yukuai3@huawei.com, martin.petersen@oracle.com,
jejb@linux.ibm.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 v6 6/6] blktrace: fix debugfs use after free
Date: Fri, 12 Jun 2020 19:42:12 -0700 [thread overview]
Message-ID: <ec643803-2339-fe8d-7f58-b37871c83386@acm.org> (raw)
In-Reply-To: <20200608170127.20419-7-mcgrof@kernel.org>
On 2020-06-08 10:01, Luis Chamberlain wrote:
> + /*
> + * Blktrace needs a debugfs name even for queues that don't register
> + * a gendisk, so it lazily registers the debugfs directory. But that
> + * can get us into a situation where a SCSI device is found, with no
> + * driver for it (yet). Then blktrace is used on the device, creating
> + * the debugfs directory, and only after that a driver is loaded. In
> + * that case we might already have a debugfs directory registered here.
> + * Even worse we could be racing with blktrace to register it.
> + */
There are LLD and ULD drivers in the SCSI subsystem. Please mention the
driver type explicitly. I assume that you are referring to SCSI ULDs
since only SCSI ULD drivers call device_add_disk()?
Could the above comment be made shorter by only mentioning that blktrace
may have been set up before or concurrently with device_add_disk() and
that device_add_disk() calls blk_register_queue()?
> case BLKTRACESETUP:
> + if (!sdp->device->request_queue->sg_debugfs_dir)
> + blk_sg_debugfs_init(sdp->device->request_queue,
> + sdp->disk->disk_name);
How about moving the sg_debugfs_dir check into blk_sg_debugfs_init()?
Thanks,
Bart.
next prev parent reply other threads:[~2020-06-13 2:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 17:01 [PATCH v6 0/8] block: fix blktrace debugfs use after free Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 1/6] block: add docs for gendisk / request_queue refcount helpers Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 2/6] block: clarify context for refcount increment helpers Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 3/6] block: revert back to synchronous request_queue removal Luis Chamberlain
2020-06-13 1:53 ` Bart Van Assche
2020-06-19 20:23 ` Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 4/6] blktrace: annotate required lock on do_blk_trace_setup() Luis Chamberlain
2020-06-09 14:18 ` Christoph Hellwig
2020-06-13 1:54 ` Bart Van Assche
2020-06-08 17:01 ` [PATCH v6 5/6] loop: be paranoid on exit and prevent new additions / removals Luis Chamberlain
2020-06-08 17:01 ` [PATCH v6 6/6] blktrace: fix debugfs use after free Luis Chamberlain
2020-06-09 15:06 ` Christoph Hellwig
2020-06-09 17:29 ` Luis Chamberlain
2020-06-09 17:32 ` Christoph Hellwig
2020-06-09 17:53 ` Luis Chamberlain
2020-06-10 6:42 ` Christoph Hellwig
2020-06-10 21:09 ` Luis Chamberlain
2020-06-10 21:52 ` Luis Chamberlain
2020-06-10 23:31 ` Luis Chamberlain
2020-06-11 5:40 ` Christoph Hellwig
2020-06-13 2:42 ` Bart Van Assche [this message]
2020-06-19 15:36 ` Luis Chamberlain
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