[PATCH v2] io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT

[Jens Axboe <axboe@kernel.dk>]

We treat EINPROGRESS like EAGAIN, but if we're retrying post getting
EINPROGRESS, then we just need to check the socket for errors and
terminate the request.

This was exposed on a bluetooth connection request which ends up
taking a while and hitting EINPROGRESS, and yields a CQE result of
-EBADFD because we're retrying a connect on a socket that is now
connected.

Cc: stable@vger.kernel.org
Fixes: 87f80d623c6c ("io_uring: handle connect -EINPROGRESS like -EAGAIN")
Link: https://github.com/axboe/liburing/issues/671
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---

Since v1:

- Send out the right version of the patch, there's no need to
  setup async data for the EINPROGRESS retry.

diff --git a/io_uring/net.c b/io_uring/net.c
index 6b69eff6887e..c2fbe8f083fb 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -46,6 +46,7 @@ struct io_connect {
 	struct file			*file;
 	struct sockaddr __user		*addr;
 	int				addr_len;
+	bool				in_progress;
 };
 
 struct io_sr_msg {
@@ -1382,6 +1383,7 @@ int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	conn->addr_len =  READ_ONCE(sqe->addr2);
+	conn->in_progress = false;
 	return 0;
 }
 
@@ -1393,6 +1395,18 @@ int io_connect(struct io_kiocb *req, unsigned int issue_flags)
 	int ret;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 
+	if (connect->in_progress) {
+		struct socket *socket;
+
+		socket = sock_from_file(req->file);
+		if (unlikely(!socket)) {
+			ret = -EBADF;
+			goto out;
+		}
+		ret = sock_error(socket->sk);
+		goto out;
+	}
+
 	if (req_has_async_data(req)) {
 		io = req->async_data;
 	} else {
@@ -1409,13 +1423,17 @@ int io_connect(struct io_kiocb *req, unsigned int issue_flags)
 	ret = __sys_connect_file(req->file, &io->address,
 					connect->addr_len, file_flags);
 	if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
-		if (req_has_async_data(req))
-			return -EAGAIN;
-		if (io_alloc_async_data(req)) {
-			ret = -ENOMEM;
-			goto out;
+		if (ret == -EINPROGRESS) {
+			connect->in_progress = true;
+		} else {
+			if (req_has_async_data(req))
+				return -EAGAIN;
+			if (io_alloc_async_data(req)) {
+				ret = -ENOMEM;
+				goto out;
+			}
+			memcpy(req->async_data, &__io, sizeof(__io));
 		}
-		memcpy(req->async_data, &__io, sizeof(__io));
 		return -EAGAIN;
 	}
 	if (ret == -ERESTARTSYS)

-- 
Jens Axboe