[PATCH AUTOSEL 4.19 58/60] nbd: make the config put is called before the notifying the waiter
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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