From: Balbir Singh <sblbir@xxxxxxxx> [ Upstream commit b224726de5e496dbf78147a66755c3d81e28bdd2 ] 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@xxxxxxxxxx> Signed-off-by: Balbir Singh <sblbir@xxxxxxxx> Reviewed-by: Keith Busch <kbusch@xxxxxxxxxx> Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/nvme/host/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index d3d6b7bd69033..28217cee5e762 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -103,10 +103,13 @@ 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) -- 2.20.1
