Commit b224726d authored Sep 18, 2019 by Balbir Singh Committed by Sagi Grimberg Sep 23, 2019

nvme-pci: Fix a race in controller removal



User space programs like udevd may try to read to partitions at the
same time the driver detects a namespace is unusable, and may deadlock
if revalidate_disk() is called while such a process is waiting to
enter the frozen queue. On detecting a dead namespace, move the disk
revalidate after unblocking dispatchers that may be holding bd_butex.

changelog Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Balbir Singh <sblbir@amzn.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

parent 0ec64895

drivers/nvme/host/core.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -102,10 +102,13 @@ static void nvme_set_queue_dying(struct nvme_ns *ns)
		*/
		if (!ns->disk \|\| test_and_set_bit(NVME_NS_DEAD, &ns->flags))
		return;
		revalidate_disk(ns->disk);
		blk_set_queue_dying(ns->queue);
		/* Forcibly unquiesce queues to avoid blocking dispatch */
		blk_mq_unquiesce_queue(ns->queue);
		/*
		* Revalidate after unblocking dispatchers that may be holding bd_butex
		*/
		revalidate_disk(ns->disk);
		}

		static void nvme_queue_scan(struct nvme_ctrl *ctrl)

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