From 03e0f3a65e4da497c3b7b213c68943cbc73a2e34 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 9 Nov 2017 19:32:07 +0800 Subject: [PATCH] nvme-pci: avoid dereference of symbol from unloaded module The 'remove_work' may be scheduled to run after nvme_remove() returns since we can't simply cancel it in nvme_remove() for avoiding deadlock. Once nvme_remove() returns, this module(nvme) can be unloaded. On the other hand, nvme_put_ctrl() calls ctr->ops->free_ctrl which may point to nvme_pci_free_ctrl() in unloaded module. This patch avoids this issue by queuing 'remove_work' via 'nvme_wq', and flush this worqueue in nvme_exit() as suggested by Sagi. Suggested-by: Sagi Grimberg Signed-off-by: Ming Lei Reviewed-by: Keith Busch Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/nvme/host/pci.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 429d56f1a19e..762b8402e04c 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -2280,7 +2280,7 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev, int status) nvme_get_ctrl(&dev->ctrl); nvme_dev_disable(dev, false); - if (!schedule_work(&dev->remove_work)) + if (!queue_work(nvme_wq, &dev->remove_work)) nvme_put_ctrl(&dev->ctrl); } @@ -2703,6 +2703,7 @@ static int __init nvme_init(void) static void __exit nvme_exit(void) { pci_unregister_driver(&nvme_driver); + flush_workqueue(nvme_wq); _nvme_check_size(); } -- 2.39.5