This is a note to let you know that I've just added the patch titled nvme-tcp: avoid race between time out and tear down to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nvme-tcp-avoid-race-between-time-out-and-tear-down.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0a37adf823cda7969016271ac0dee0e160f9eca8 Author: Chao Leng <lengchao@xxxxxxxxxx> Date: Thu Oct 22 10:15:15 2020 +0800 nvme-tcp: avoid race between time out and tear down [ Upstream commit d6f66210f4b1aa2f5944f0e34e0f8db44f499f92 ] Now use teardown_lock to serialize for time out and tear down. This may cause abnormal: first cancel all request in tear down, then time out may complete the request again, but the request may already be freed or restarted. To avoid race between time out and tear down, in tear down process, first we quiesce the queue, and then delete the timer and cancel the time out work for the queue. At the same time we need to delete teardown_lock. Signed-off-by: Chao Leng <lengchao@xxxxxxxxxx> Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index e159b78b5f3b4..76440f26c1453 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -110,7 +110,6 @@ struct nvme_tcp_ctrl { struct sockaddr_storage src_addr; struct nvme_ctrl ctrl; - struct mutex teardown_lock; struct work_struct err_work; struct delayed_work connect_work; struct nvme_tcp_request async_req; @@ -1797,8 +1796,8 @@ out_free_queue: static void nvme_tcp_teardown_admin_queue(struct nvme_ctrl *ctrl, bool remove) { - mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock); blk_mq_quiesce_queue(ctrl->admin_q); + blk_sync_queue(ctrl->admin_q); nvme_tcp_stop_queue(ctrl, 0); if (ctrl->admin_tagset) { blk_mq_tagset_busy_iter(ctrl->admin_tagset, @@ -1808,18 +1807,17 @@ static void nvme_tcp_teardown_admin_queue(struct nvme_ctrl *ctrl, if (remove) blk_mq_unquiesce_queue(ctrl->admin_q); nvme_tcp_destroy_admin_queue(ctrl, remove); - mutex_unlock(&to_tcp_ctrl(ctrl)->teardown_lock); } static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl, bool remove) { - mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock); if (ctrl->queue_count <= 1) - goto out; + return; blk_mq_quiesce_queue(ctrl->admin_q); nvme_start_freeze(ctrl); nvme_stop_queues(ctrl); + nvme_sync_io_queues(ctrl); nvme_tcp_stop_io_queues(ctrl); if (ctrl->tagset) { blk_mq_tagset_busy_iter(ctrl->tagset, @@ -1829,8 +1827,6 @@ static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl, if (remove) nvme_start_queues(ctrl); nvme_tcp_destroy_io_queues(ctrl, remove); -out: - mutex_unlock(&to_tcp_ctrl(ctrl)->teardown_lock); } static void nvme_tcp_reconnect_or_remove(struct nvme_ctrl *ctrl) @@ -2074,14 +2070,11 @@ static void nvme_tcp_complete_timed_out(struct request *rq) struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq); struct nvme_ctrl *ctrl = &req->queue->ctrl->ctrl; - /* fence other contexts that may complete the command */ - mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock); nvme_tcp_stop_queue(ctrl, nvme_tcp_queue_id(req->queue)); if (!blk_mq_request_completed(rq)) { nvme_req(rq)->status = NVME_SC_HOST_ABORTED_CMD; blk_mq_complete_request(rq); } - mutex_unlock(&to_tcp_ctrl(ctrl)->teardown_lock); } static enum blk_eh_timer_return @@ -2344,7 +2337,6 @@ static struct nvme_ctrl *nvme_tcp_create_ctrl(struct device *dev, nvme_tcp_reconnect_ctrl_work); INIT_WORK(&ctrl->err_work, nvme_tcp_error_recovery_work); INIT_WORK(&ctrl->ctrl.reset_work, nvme_reset_ctrl_work); - mutex_init(&ctrl->teardown_lock); if (!(opts->mask & NVMF_OPT_TRSVCID)) { opts->trsvcid =