diff options
| author | Sun Ke | 2020-01-22 11:18:57 +0800 |
|---|---|---|
| committer | Jens Axboe | 2020-01-29 21:05:53 -0700 |
| commit | 5c0dd228b5fc30a3b732c7ae2657e0161ec7ed80 (patch) | |
| tree | f42e9604422c696d51a58481bdb4162a7c58988b | |
| parent | 6a365874a43c43b227492266f59cd68ecc5a6f83 (diff) | |
nbd: add a flush_workqueue in nbd_start_device
When kzalloc fail, may cause trying to destroy the
workqueue from inside the workqueue.
If num_connections is m (2 < m), and NO.1 ~ NO.n
(1 < n < m) kzalloc are successful. The NO.(n + 1)
failed. Then, nbd_start_device will return ENOMEM
to nbd_start_device_ioctl, and nbd_start_device_ioctl
will return immediately without running flush_workqueue.
However, we still have n recv threads. If nbd_release
run first, recv threads may have to drop the last
config_refs and try to destroy the workqueue from
inside the workqueue.
To fix it, add a flush_workqueue in nbd_start_device.
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/nbd.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index b4607dd96185..78181908f0df 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1265,6 +1265,16 @@ static int nbd_start_device(struct nbd_device *nbd) args = kzalloc(sizeof(*args), GFP_KERNEL); if (!args) { sock_shutdown(nbd); + /* + * If num_connections is m (2 < m), + * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful. + * But NO.(n + 1) failed. We still have n recv threads. + * So, add flush_workqueue here to prevent recv threads + * dropping the last config_refs and trying to destroy + * the workqueue from inside the workqueue. + */ + if (i) + flush_workqueue(nbd->recv_workq); return -ENOMEM; } sk_set_memalloc(config->socks[i]->sock->sk); |