From: Bart Van Assche <bvanassche@acm.org>
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: [PATCH 4/4] Fix race between starved list processing and device removal
Date: Wed, 10 Oct 2012 17:10:35 +0200 [thread overview]
Message-ID: <50758FEB.9090602@acm.org> (raw)
In-Reply-To: <50758EBE.7050202@acm.org>
Avoid that the sdev reference count can drop to zero before
the queue is run by scsi_run_queue(). Also avoid that the sdev
reference count can drop to zero in the same function by invoking
__blk_run_queue().
Reported-and-tested-by: Chanho Min <chanho.min@lge.com>
Reference: http://lkml.org/lkml/2012/8/2/96
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/scsi/scsi_lib.c | 5 +++++
drivers/scsi/scsi_sysfs.c | 7 ++++++-
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0e15374..fb57e68 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -452,10 +452,15 @@ static void scsi_run_queue(struct request_queue *q)
continue;
}
+ get_device(&sdev->sdev_gendev);
spin_unlock(shost->host_lock);
+
spin_lock(sdev->request_queue->queue_lock);
__blk_run_queue(sdev->request_queue);
spin_unlock(sdev->request_queue->queue_lock);
+
+ put_device(&sdev->sdev_gendev);
+
spin_lock(shost->host_lock);
}
/* put any unprocessed entries back */
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index ce5224c..2661a957 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)
@@ -977,6 +978,10 @@ void __scsi_remove_device(struct scsi_device *sdev)
blk_cleanup_queue(sdev->request_queue);
cancel_work_sync(&sdev->requeue_work);
+ spin_lock_irqsave(shost->host_lock, flags);
+ list_del(&sdev->starved_entry);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
--
1.7.10.4
next prev parent reply other threads:[~2012-10-10 15:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-10 15:05 [PATCH 0/4 v4] More device removal fixes Bart Van Assche
2012-10-10 15:07 ` [PATCH 1/4] block: Rename queue dead flag Bart Van Assche
2012-10-16 23:31 ` Tejun Heo
2012-10-10 15:08 ` [PATCH 2/4] block: Avoid that request_fn is invoked on a dead queue Bart Van Assche
2012-10-16 23:38 ` Tejun Heo
2012-10-23 12:11 ` Bart Van Assche
2012-10-24 19:13 ` Tejun Heo
2012-10-10 15:09 ` [PATCH 3/4] Make blk_cleanup_queue() wait until request_fn finished Bart Van Assche
2012-10-16 23:51 ` Tejun Heo
2012-10-23 12:16 ` Bart Van Assche
2012-10-24 19:11 ` Tejun Heo
2012-10-10 15:10 ` Bart Van Assche [this message]
2012-10-16 23:59 ` [PATCH 4/4] Fix race between starved list processing and device removal Tejun Heo
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=50758FEB.9090602@acm.org \
--to=bvanassche@acm.org \
--cc=axboe@kernel.dk \
--cc=chanho.min@lge.com \
--cc=jbottomley@parallels.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).