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| author |   Xie Yongji <xieyongji@bytedance.com> | 2021-08-13 23:13:30 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2021-08-13 09:46:48 -0600 |
| commit | cddce01160582a5f52ada3da9626c052d852ec42 (patch) | |
| tree | e7615b6f592123a288f26ad9e64dd7381bafaf30 /drivers/block/nbd.c | |
| parent | blk-mq: clear active_queues before clearing BLK_MQ_F_TAG_QUEUE_SHARED (diff) | |
| download | linux-dev-cddce01160582a5f52ada3da9626c052d852ec42.tar.xz linux-dev-cddce01160582a5f52ada3da9626c052d852ec42.zip | |
nbd: Aovid double completion of a request
There is a race between iterating over requests in
nbd_clear_que() and completing requests in recv_work(),
which can lead to double completion of a request.
To fix it, flush the recv worker before iterating over
the requests and don't abort the completed request
while iterating.
Fixes: 96d97e17828f ("nbd: clear_sock on netlink disconnect")
Reported-by: Jiang Yadong <jiangyadong@bytedance.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210813151330.96-1-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '')
| -rw-r--r-- | drivers/block/nbd.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index c38317979f74..19f5d5a8b16a 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -818,6 +818,10 @@ static bool nbd_clear_req(struct request *req, void *data, bool reserved) { struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); + /* don't abort one completed request */ + if (blk_mq_request_completed(req)) + return true; + mutex_lock(&cmd->lock); cmd->status = BLK_STS_IOERR; mutex_unlock(&cmd->lock); @@ -2004,15 +2008,19 @@ static void nbd_disconnect_and_put(struct nbd_device *nbd) { mutex_lock(&nbd->config_lock); nbd_disconnect(nbd); - nbd_clear_sock(nbd); - mutex_unlock(&nbd->config_lock); + sock_shutdown(nbd); /* * Make sure recv thread has finished, so it does not drop the last * config ref and try to destroy the workqueue from inside the work - * queue. + * queue. And this also ensure that we can safely call nbd_clear_que() + * to cancel the inflight I/Os. */ if (nbd->recv_workq) flush_workqueue(nbd->recv_workq); + nbd_clear_que(nbd); + nbd->task_setup = NULL; + mutex_unlock(&nbd->config_lock); + if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, &nbd->config->runtime_flags)) nbd_config_put(nbd); |