From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
Alan Stern <stern@rowland.harvard.edu>,
Hannes Reinecke <hare@suse.de>,
Joe Breuer <linux-kernel@jmbreuer.net>,
Bart Van Assche <bvanassche@acm.org>,
Bagas Sanjaya <bagasdotme@gmail.com>, Pavel Machek <pavel@ucw.cz>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <len.brown@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kees Cook <keescook@chromium.org>,
Tony Luck <tony.luck@intel.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Thorsten Leemhuis <linux@leemhuis.info>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Phillip Potter <phil@philpotter.co.uk>,
Linux Power Management <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Hardening <linux-hardening@vger.kernel.org>,
Linux Regressions <regressions@lists.linux.dev>,
Linux SCSI <linux-scsi@vger.kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Hannes Reinecke <hare@suse.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Martin Kepplinger <martin.kepplinger@puri.sm>,
Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: Re: Fwd: Waking up from resume locks up on sr device
Date: Thu, 15 Jun 2023 07:09:47 +0200 [thread overview]
Message-ID: <20230615050947.GA5053@lst.de> (raw)
In-Reply-To: <9633f1a6-2e33-4a40-3fdb-0c1c4e4cd720@kernel.org>
On Thu, Jun 15, 2023 at 01:57:37PM +0900, Damien Le Moal wrote:
> > No. scsi_device_get just increments a reference count, and thus
> > prevents ->release from beeing called. ->remove is not in any way
> > affected by the refcount.
>
> What ->remove cb are you talking about ? The gendev one ?
The one for the device locked.
> I am trying to understand why the use of device_lock() helps in any way given
> that this is not used by any other functions in scsi. And given that
The device model locks the device before calling ->remove.
> scsi_rescan_device() should always be called with a ref on the scsi device (and
> so on the gendev as well) held, why would this function be racy with device remove ?
Because ->remove ould otherwise be called at the same time as ->rescan.
> Note that I did find a couple of places where scsi_rescan_device() seems to not
> be called with a reference to the scsi dev held, e.g. store_rescan_field() and
> store_state_field().
You need both a valid reference and ensure ->remove is not called at the
same time.
next prev parent reply other threads:[~2023-06-15 5:10 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 11:04 Fwd: Waking up from resume locks up on sr device Bagas Sanjaya
2023-06-10 6:38 ` Bagas Sanjaya
2023-06-10 8:55 ` Pavel Machek
2023-06-10 13:27 ` Bagas Sanjaya
2023-06-10 15:03 ` Bart Van Assche
2023-06-11 9:05 ` Joe Breuer
2023-06-11 11:31 ` Bagas Sanjaya
2023-06-14 4:49 ` Damien Le Moal
2023-06-14 5:37 ` Kai-Heng Feng
2023-06-14 6:31 ` Damien Le Moal
2023-06-14 7:22 ` Damien Le Moal
2023-06-14 6:57 ` Hannes Reinecke
2023-06-14 7:35 ` Damien Le Moal
2023-06-14 14:26 ` Alan Stern
2023-06-14 14:40 ` Rafael J. Wysocki
2023-06-14 18:04 ` Bart Van Assche
2023-06-14 22:44 ` Damien Le Moal
2023-06-15 0:10 ` Damien Le Moal
2023-06-15 4:40 ` Christoph Hellwig
2023-06-15 4:57 ` Damien Le Moal
2023-06-15 5:09 ` Christoph Hellwig [this message]
2023-06-12 3:09 ` Damien Le Moal
2023-06-12 6:09 ` Hannes Reinecke
2023-06-12 7:22 ` Damien Le Moal
2023-06-12 7:36 ` Kai-Heng Feng
2023-06-12 7:47 ` Damien Le Moal
2023-06-12 14:33 ` Alan Stern
2023-06-12 15:37 ` Rafael J. Wysocki
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