On Fri, 22 May 2015, Parav Pandit wrote:
During normal positive path probe, (a) device is added to dev_list in nvme_dev_start() (b) nvme_kthread got created, which will eventually refers to dev->queues[qid] to check for NULL. (c) dev_start() worker thread has started probing device and creating the queue using nvme_alloc_queue This is is assigning the dev->queue[qid] new pointer. If this is done out of order, nvme_kthread will pickup uninitialized q_lock, cq_phase, q_db.
A memory barrier before incrementing the dev->queue_count (and assigning the pointer in the array before that) should address this concern.
Other thoughts to not create nvme_kthread until all the queues are active.
No good, we want to poll during queue creation to detect controller errors and broken interrupts. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/