UPSTREAM: io_uring: Clean up a false-positive warning from GCC 9.3.0
commit 0d7c1153d9291197c1dc473cfaade77acb874b4b upstream.
In io_recv(), if import_single_range() fails, the @flags variable is
uninitialized, then it will goto out_free.
After the goto, the compiler doesn't know that (ret < min_ret) is
always true, so it thinks the "if ((flags & MSG_WAITALL) ..." path
could be taken.
The complaint comes from gcc-9 (Debian 9.3.0-22) 9.3.0:
```
fs/io_uring.c:5238 io_recvfrom() error: uninitialized symbol 'flags'
```
Fix this by bypassing the @ret and @flags check when
import_single_range() fails.
Reasons:
1. import_single_range() only returns -EFAULT when it fails.
2. At that point, @flags is uninitialized and shouldn't be read.
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Reported-by: "Chen, Rong A" <[email protected]>
Link: https://lore.gnuweeb.org/timl/[email protected]/
Cc: Pavel Begunkov <[email protected]>
Suggested-by: Ammar Faizi <[email protected]>
Fixes: 7297ce3d59449de49d3c9e1f64ae25488750a1fc ("io_uring: improve send/recv error handling")
Change-Id: Ifd324b3213a0682dae11177c93a5b8272516c2cd
Signed-off-by: Alviro Iskandar Setiawan <[email protected]>
Signed-off-by: Ammar Faizi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Bug: 268174392
(cherry picked from commit ddaaadf22bea31cf7e94d55c6530ce75947bb1cc)
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 9c3acfdc..0eed453 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -5104,7 +5104,6 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
min_ret = iov_iter_count(&msg.msg_iter);
ret = sock_recvmsg(sock, &msg, flags);
-out_free:
if (ret < min_ret) {
if (ret == -EAGAIN && force_nonblock)
return -EAGAIN;
@@ -5119,6 +5118,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
}
req_set_fail(req);
} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
+out_free:
req_set_fail(req);
}
if (req->flags & REQ_F_BUFFER_SELECTED)
