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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pavel Begunkov <asml.silence@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 5.10 519/717] io_uring: fix ignoring xa_store errors
Date:   Mon, 28 Dec 2020 13:48:37 +0100
Message-Id: <20201228125045.824895237@linuxfoundation.org>
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From: Pavel Begunkov <asml.silence@gmail.com>

commit a528b04ea40690ff40501f50d618a62a02b19620 upstream.

xa_store() may fail, check the result.

Cc: stable@vger.kernel.org # 5.10
Fixes: 0f2122045b946 ("io_uring: don't rely on weak ->files references")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/io_uring.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8708,10 +8708,9 @@ static void io_uring_cancel_task_request
 static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
 {
 	struct io_uring_task *tctx = current->io_uring;
+	int ret;
 
 	if (unlikely(!tctx)) {
-		int ret;
-
 		ret = io_uring_alloc_task_context(current);
 		if (unlikely(ret))
 			return ret;
@@ -8722,7 +8721,12 @@ static int io_uring_add_task_file(struct
 
 		if (!old) {
 			get_file(file);
-			xa_store(&tctx->xa, (unsigned long)file, file, GFP_KERNEL);
+			ret = xa_err(xa_store(&tctx->xa, (unsigned long)file,
+						file, GFP_KERNEL));
+			if (ret) {
+				fput(file);
+				return ret;
+			}
 		}
 		tctx->last = file;
 	}