On Tue, Aug 7, 2012 at 2:56 AM, Bart Van Assche <bvanassche@xxxxxxx> wrote: > Indeed. How about the patch below ? Scsi devices are removed from > starved_list after blk_cleanup_queue() and before put_device(). That > guarantees that inside scsi_run_queue() get_device() under host lock > will succeed. Thanks, IMHO, it's harmless and the simple way to solve this issue. But, I think the second half of your patches are not required, extra referecne is might suffice? In addition, Is it ironic that we are careful to use put_device at scsi_request_fn?. If we trigger the ->remove(), It occur a oops. What about the removal of unlock/lock as patch bellow? diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 4037fd5..8d9eccd 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1608,11 +1608,7 @@ out_delay: if (sdev->device_busy == 0) blk_delay_queue(q, SCSI_QUEUE_DELAY); out: - /* must be careful here...if we trigger the ->remove() function - * we cannot be holding the q lock */ - spin_unlock_irq(q->queue_lock); put_device(&sdev->sdev_gendev); - spin_lock_irq(q->queue_lock); } u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html