From: Yu Kuai <yukuai3@huawei.com>
To: <axboe@kernel.dk>, <josef@toxicpanda.com>, <ming.lei@redhat.com>,
<bvanassche@acm.org>
Cc: <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<nbd@other.debian.org>, <yukuai3@huawei.com>,
<yi.zhang@huawei.com>
Subject: [PATCH v3 3/5] nbd: don't handle response without a corresponding request message
Date: Tue, 24 Aug 2021 22:12:25 +0800 [thread overview]
Message-ID: <20210824141227.808340-4-yukuai3@huawei.com> (raw)
In-Reply-To: <20210824141227.808340-1-yukuai3@huawei.com>
While handling a response message from server, nbd_read_stat() will
try to get request by tag, and then complete the request. However,
this is problematic if nbd haven't sent a corresponding request
message:
t1 t2
submit_bio
nbd_queue_rq
blk_mq_start_request
recv_work
nbd_read_stat
blk_mq_get_rq_by_tag
blk_mq_complete_request
nbd_send_cmd
Thus add a new cmd flag 'NBD_CMD_INFLIGHT', it will be set in
nbd_send_cmd() and checked in nbd_read_stat().
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
drivers/block/nbd.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index ca54a0736090..7b9e19675224 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -127,6 +127,11 @@ struct nbd_device {
};
#define NBD_CMD_REQUEUED 1
+/*
+ * This flag will be set if nbd_send_cmd() succeed, and will be checked in
+ * normal completion.
+ */
+#define NBD_CMD_INFLIGHT 2
struct nbd_cmd {
struct nbd_device *nbd;
@@ -743,6 +748,12 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
cmd = blk_mq_rq_to_pdu(req);
mutex_lock(&cmd->lock);
+ if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
+ dev_err(disk_to_dev(nbd->disk), "NBD_CMD_INFLIGHT is not set %d\n",
+ tag);
+ ret = -ENOENT;
+ goto out;
+ }
if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
@@ -980,6 +991,8 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
* returns EAGAIN can be retried on a different socket.
*/
ret = nbd_send_cmd(nbd, cmd, index);
+ if (!ret)
+ set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
if (ret == -EAGAIN) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Request send failed, requeueing\n");
--
2.31.1
next prev parent reply other threads:[~2021-08-24 14:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 14:12 [PATCH v3 0/5] fix request uaf in nbd_read_stat() Yu Kuai
2021-08-24 14:12 ` [PATCH v3 1/5] blk-mq: add a new interface to get request by tag Yu Kuai
2021-08-24 14:12 ` [PATCH v3 2/5] nbd: convert to use blk_mq_get_rq_by_tag() Yu Kuai
2021-08-24 14:12 ` Yu Kuai [this message]
2021-08-24 14:12 ` [PATCH v3 4/5] nbd: make sure request completion won't concurrent Yu Kuai
2021-08-24 14:12 ` [PATCH v3 5/5] nbd: don't start request if nbd_queue_rq() failed Yu Kuai
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