From: Dan Carpenter <dan.carpenter@oracle.com>
To: Wenchao Hao <haowenchao@huawei.com>
Cc: fmdefrancesco@gmail.com, axboe@kernel.dk, jejb@linux.ibm.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
syzbot+f08c77040fa163a75a46@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com, linfeilong@huawei.com
Subject: Re: [PATCH] scsi: sd: call device_del() if device_add_disk() fails
Date: Thu, 31 Mar 2022 08:41:56 +0300 [thread overview]
Message-ID: <20220331054156.GI3293@kadam> (raw)
In-Reply-To: <20220331152622.616534-1-haowenchao@huawei.com>
On Thu, Mar 31, 2022 at 11:26:22AM -0400, 'Wenchao Hao' via syzkaller-bugs wrote:
> I do not think it's necessary to call device_del() on this path. If the device
> has been added, put_device() would delete it from sysfs. So the origin error
> handle is ok with me.
>
No. The original is buggy and it was detected at runtime by syzbot.
It's not static analysis, it is an actual bug found in testing.
The device_put() unwinds device_initialize(). The device_del() unwinds
device_add(). Take a look at the comments to device_add() or take a
look at how device_register/unregister() work.
The temptation was to call device_unregister() which is a combined
device_del(); device_put(); but when the device_initialize() and
device_add() are called separately, then I think it is more readable to
call del and put separately as well.
regards,
dan carpenter
next prev parent reply other threads:[~2022-03-31 5:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-29 15:49 [PATCH] scsi: sd: call device_del() if device_add_disk() fails Fabio M. De Francesco
2022-03-30 4:30 ` Dan Carpenter
2022-03-31 15:26 ` Wenchao Hao
2022-03-31 5:41 ` Dan Carpenter [this message]
2022-03-31 5:45 ` Christoph Hellwig
2022-03-31 9:07 ` Fabio M. De Francesco
2022-03-31 9:13 ` Christoph Hellwig
2022-03-31 10:13 ` Fabio M. De Francesco
2022-03-31 12:14 ` Wenchao Hao
2022-03-31 13:42 ` Dan Carpenter
2022-03-31 14:19 ` James Bottomley
2022-03-31 15:11 ` Dan Carpenter
2022-03-31 16:14 ` Fabio M. De Francesco
2022-03-31 16:24 ` Dan Carpenter
2022-03-31 17:21 ` Fabio M. De Francesco
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