[PATCH 5.7 075/244] io_uring: fix recvmsg memory leak with buffer selection

[Greg Kroah-Hartman]

From: Pavel Begunkov <asml.sile...@gmail.com>

commit 681fda8d27a66f7e65ff7f2d200d7635e64a8d05 upstream.

io_recvmsg() doesn't free memory allocated for struct io_buffer. This can
causes a leak when used with automatic buffer selection.

Signed-off-by: Pavel Begunkov <asml.sile...@gmail.com>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 fs/io_uring.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3884,10 +3884,16 @@ static int io_recvmsg(struct io_kiocb *r
 
                ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.msg,
                                                kmsg->uaddr, flags);
-               if (force_nonblock && ret == -EAGAIN)
-                       return io_setup_async_msg(req, kmsg);
+               if (force_nonblock && ret == -EAGAIN) {
+                       ret = io_setup_async_msg(req, kmsg);
+                       if (ret != -EAGAIN)
+                               kfree(kbuf);
+                       return ret;
+               }
                if (ret == -ERESTARTSYS)
                        ret = -EINTR;
+               if (kbuf)
+                       kfree(kbuf);
        }
 
        if (kmsg && kmsg->iov != kmsg->fast_iov)