From 87aac3a80af5cbad93e63250e8a1e19095ba0d30 Mon Sep 17 00:00:00 2001 From: Xiubo Li Date: Tue, 13 Oct 2020 22:45:14 -0400 Subject: nbd: make the config put is called before the notifying the waiter There has one race case for ceph's rbd-nbd tool. When do mapping it may fail with EBUSY from ioctl(nbd, NBD_DO_IT), but actually the nbd device has already unmaped. It dues to if just after the wake_up(), the recv_work() is scheduled out and defers calling the nbd_config_put(), though the map process has exited the "nbd->recv_task" is not cleared. Signed-off-by: Xiubo Li Reviewed-by: Josef Bacik Signed-off-by: Jens Axboe --- drivers/block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/block') diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 2dca0aab0a9a..90c2effb5ded 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -802,9 +802,9 @@ static void recv_work(struct work_struct *work) if (likely(!blk_should_fake_timeout(rq->q))) blk_mq_complete_request(rq); } + nbd_config_put(nbd); atomic_dec(&config->recv_threads); wake_up(&config->recv_wq); - nbd_config_put(nbd); kfree(args); } -- cgit v1.2.3