Dongli Zhang 9210c075ce nvme-pci: avoid race between nvme_reap_pending_cqes() and nvme_poll() ... There may be a race between nvme_reap_pending_cqes() and nvme_poll(), e.g., when doing live reset while polling the nvme device. CPU X CPU Y nvme_poll() nvme_dev_disable() -> nvme_stop_queues() -> nvme_suspend_io_queues() -> nvme_suspend_queue() -> spin_lock(&nvmeq->cq_poll_lock); -> nvme_reap_pending_cqes() -> nvme_process_cq() -> nvme_process_cq() In the above scenario, the nvme_process_cq() for the same queue may be running on both CPU X and CPU Y concurrently. It is much more easier to reproduce the issue when CONFIG_PREEMPT is enabled in kernel. When CONFIG_PREEMPT is disabled, it would take longer time for nvme_stop_queues()-->blk_mq_quiesce_queue() to wait for grace period. This patch protects nvme_process_cq() with nvmeq->cq_poll_lock in nvme_reap_pending_cqes(). Fixes: fa46c6fb5d ("nvme/pci: move cqe check after device shutdown") Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de>		2020-05-27 20:32:56 +02:00
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host	nvme-pci: avoid race between nvme_reap_pending_cqes() and nvme_poll()	2020-05-27 20:32:56 +02:00
target	block-5.7-2020-04-10	2020-04-10 10:06:54 -07:00
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00