From: Bart Van Assche <bvanassche@acm.org>
To: "Zhuang, Jin Can" <jin.can.zhuang@intel.com>
Cc: linux-scsi <linux-scsi@vger.kernel.org>,
James Bottomley <jbottomley@parallels.com>,
Mike Christie <michaelc@cs.wisc.edu>,
Jens Axboe <axboe@kernel.dk>, Tejun Heo <tj@kernel.org>,
Chanho Min <chanho.min@lge.com>
Subject: Re: [PATCH 6/7] Fix race between starved list processing and device removal
Date: Wed, 21 Nov 2012 12:06:35 +0100 [thread overview]
Message-ID: <50ACB5BB.6060409@acm.org> (raw)
In-Reply-To: <5093A4E5.20207@acm.org>
On 11/02/12 11:48, Bart Van Assche wrote:
> [PATCH] Fix race between starved list processing and device removal
> [ ... ]
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index ce5224c..2f0f31e 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -348,7 +348,6 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
> starget->reap_ref++;
> list_del(&sdev->siblings);
> list_del(&sdev->same_target_siblings);
> - list_del(&sdev->starved_entry);
> spin_unlock_irqrestore(sdev->host->host_lock, flags);
>
> cancel_work_sync(&sdev->event_work);
> @@ -956,6 +955,8 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
> void __scsi_remove_device(struct scsi_device *sdev)
> {
> struct device *dev = &sdev->sdev_gendev;
> + struct Scsi_Host *shost = sdev->host;
> + unsigned long flags;
>
> if (sdev->is_visible) {
> if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
> @@ -973,7 +974,13 @@ void __scsi_remove_device(struct scsi_device *sdev)
> * scsi_run_queue() invocations have finished before tearing down the
> * device.
> */
> +
> scsi_device_set_state(sdev, SDEV_DEL);
> +
> + spin_lock_irqsave(shost->host_lock, flags);
> + list_del(&sdev->starved_entry);
> + spin_unlock_irqrestore(shost->host_lock, flags);
> +
> blk_cleanup_queue(sdev->request_queue);
> cancel_work_sync(&sdev->requeue_work);
>
Please ignore this patch. Even with this patch applied there is still a
race condition present, namely that the __blk_run_queue() call in
scsi_run_queue() can get invoked after __scsi_remove_device() invoked
put_device().
Bart.
next prev parent reply other threads:[~2012-11-21 11:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 12:00 [PATCH 0/7 v5] More device removal fixes Bart Van Assche
2012-10-26 12:01 ` [PATCH 1/7] block: Avoid that blk_drain_queue() finishes early Bart Van Assche
2012-10-29 1:47 ` Tejun Heo
2012-10-29 1:52 ` Tejun Heo
2012-10-29 14:35 ` Bart Van Assche
2012-10-26 12:02 ` [PATCH 2/7] block: Let blk_drain_queue() caller obtain the queue lock Bart Van Assche
2012-10-29 1:55 ` Tejun Heo
2012-10-26 12:02 ` [PATCH 3/7] block: Rename queue dead flag Bart Van Assche
2012-10-26 12:03 ` [PATCH 4/7] block: Avoid that request_fn is invoked on a dead queue Bart Van Assche
2012-10-29 1:59 ` Tejun Heo
2012-10-26 12:04 ` [PATCH 5/7] block: Make blk_cleanup_queue() wait until request_fn finished Bart Van Assche
2012-10-29 2:00 ` Tejun Heo
2012-10-26 12:05 ` [PATCH 6/7] Fix race between starved list processing and device removal Bart Van Assche
2012-10-28 18:01 ` Zhuang, Jin Can
2012-10-29 14:32 ` Bart Van Assche
2012-10-30 5:40 ` Zhuang, Jin Can
2012-11-02 10:48 ` Bart Van Assche
2012-11-21 11:06 ` Bart Van Assche [this message]
[not found] ` <026701cdb8c3$d2e3cb50$78ab61f0$@min@lge.com>
2012-11-21 12:10 ` Bart Van Assche
2012-10-29 2:07 ` Tejun Heo
2012-10-26 12:05 ` [PATCH 7/7] Remove get_device() / put_device() pair from scsi_request_fn() Bart Van Assche
2012-10-29 2:08 ` Tejun Heo
2012-11-23 10:37 ` [PATCH 0/7 v5] More device removal fixes Bart Van Assche
2012-11-26 17:19 ` Bart Van Assche
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=50ACB5BB.6060409@acm.org \
--to=bvanassche@acm.org \
--cc=axboe@kernel.dk \
--cc=chanho.min@lge.com \
--cc=jbottomley@parallels.com \
--cc=jin.can.zhuang@intel.com \
--cc=linux-scsi@vger.kernel.org \
--cc=michaelc@cs.wisc.edu \
--cc=tj@kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.