Re: FAILED: patch "[PATCH] io_uring/rw: ensure io->bytes_done is always initialized" failed to apply to 5.15-stable tree

[Jens Axboe <axboe@kernel.dk>]

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On 1/22/24 12:27 PM, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.15-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

This one applies to 5.10 and 5.15 stable, it should go into both.
It's the same patch, just in the older bigger unified file.

-- 
Jens Axboe


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From 2fb96ecf68bc1fb55508d22ebaf9518eaeb1a088 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 22 Jan 2024 12:30:07 -0700
Subject: [PATCH] io_uring/rw: ensure io->bytes_done is always initialized

commit 0a535eddbe0dc1de4386046ab849f08aeb2f8faf upstream.

If IOSQE_ASYNC is set and we fail importing an iovec for a readv or
writev request, then we leave ->bytes_done uninitialized and hence the
eventual failure CQE posted can potentially have a random res value
rather than the expected -EINVAL.

Setup ->bytes_done before potentially failing, so we have a consistent
value if we fail the request early.

Cc: stable@vger.kernel.org
Reported-by: xingwei lee <xrivendell7@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/io_uring.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 30535d4edee7..55fd6d98fe12 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3490,14 +3490,17 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
 	struct iovec *iov = iorw->fast_iov;
 	int ret;
 
+	iorw->bytes_done = 0;
+	iorw->free_iovec = NULL;
+
 	ret = io_import_iovec(rw, req, &iov, &iorw->iter, false);
 	if (unlikely(ret < 0))
 		return ret;
 
-	iorw->bytes_done = 0;
-	iorw->free_iovec = iov;
-	if (iov)
+	if (iov) {
+		iorw->free_iovec = iov;
 		req->flags |= REQ_F_NEED_CLEANUP;
+	}
 	iov_iter_save_state(&iorw->iter, &iorw->iter_state);
 	return 0;
 }
-- 
2.43.0