From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: [PATCH 4/4] Fix race between starved list processing and device removal Date: Wed, 10 Oct 2012 17:10:35 +0200 Message-ID: <50758FEB.9090602@acm.org> References: <50758EBE.7050202@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from gerard.telenet-ops.be ([195.130.132.48]:39388 "EHLO gerard.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932302Ab2JJPKg (ORCPT ); Wed, 10 Oct 2012 11:10:36 -0400 In-Reply-To: <50758EBE.7050202@acm.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org Cc: linux-scsi , James Bottomley , Mike Christie , Jens Axboe , Tejun Heo , Chanho Min 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 Reference: http://lkml.org/lkml/2012/8/2/96 Cc: Jens Axboe Cc: Tejun Heo Cc: Reviewed-by: Mike Christie Signed-off-by: Bart Van Assche --- 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