[PATCH] io_uring/net: clear msg_controllen on partial sendmsg retry

[Jens Axboe <axboe@kernel.dk>]

If we have cmsg attached AND we transferred partial data at least, clear
msg_controllen on retry so we don't attempt to send that again.

Cc: stable@vger.kernel.org # 5.10+
Fixes: cac9e4418f4c ("io_uring/net: save msghdr->msg_control for retries")
Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---

diff --git a/io_uring/net.c b/io_uring/net.c
index 51b0f7fbb4f5..fe1c478c7dec 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -326,6 +326,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
 			return io_setup_async_msg(req, kmsg, issue_flags);
 		if (ret > 0 && io_net_retry(sock, flags)) {
+			kmsg->msg.msg_controllen = 0;
 			sr->done_io += ret;
 			req->flags |= REQ_F_PARTIAL_IO;
 			return io_setup_async_msg(req, kmsg, issue_flags);

-- 
Jens Axboe