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
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