Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 58/60] nbd: make the config put is called before the notifying the waiter | Date | Mon, 26 Oct 2020 20:04:13 -0400 |
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From: Xiubo Li <xiubli@redhat.com>
[ Upstream commit 87aac3a80af5cbad93e63250e8a1e19095ba0d30 ]
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 <xiubli@redhat.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index d7c7232e438c9..52e1e71e81241 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -740,9 +740,9 @@ static void recv_work(struct work_struct *work) blk_mq_complete_request(blk_mq_rq_from_pdu(cmd)); } + nbd_config_put(nbd); atomic_dec(&config->recv_threads); wake_up(&config->recv_wq); - nbd_config_put(nbd); kfree(args); } -- 2.25.1
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