From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: [PATCH] Fix race between starved list processing and device removal Date: Thu, 09 Aug 2012 18:59:24 +0000 Message-ID: <5024088C.9060205@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from relay04ant.iops.be ([212.53.5.219]:33977 "EHLO relay04ant.iops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185Ab2HIS7a (ORCPT ); Thu, 9 Aug 2012 14:59:30 -0400 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi , Chanho Min , Jens Axboe , Tejun Heo , James Bottomley 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-by: Chanho Min Reference: http://lkml.org/lkml/2012/8/2/96 Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie Cc: Jens Axboe Cc: Tejun Heo Cc: --- drivers/scsi/scsi_lib.c | 5 +++++ drivers/scsi/scsi_sysfs.c | 7 ++++++- 2 files changed, 11 insertions(+), 1 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index ffd7773..bd7daec 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 093d4f6..44f232e 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); -- 1.7.7