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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>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.17 172/219] io_uring: zero tag on rsrc removal
Date:   Mon, 18 Apr 2022 14:12:21 +0200
Message-Id: <20220418121211.694562414@linuxfoundation.org>
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From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit 8f0a24801bb44aa58496945aabb904c729176772 ]

Automatically default rsrc tag in io_queue_rsrc_removal(), it's safer
than leaving it there and relying on the rest of the code to behave and
not use it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1cf262a50df17478ea25b22494dcc19f3a80301f.1649336342.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6f93bff7633c..53b20d8b1129 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8536,13 +8536,15 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
 static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
 				 struct io_rsrc_node *node, void *rsrc)
 {
+	u64 *tag_slot = io_get_tag_slot(data, idx);
 	struct io_rsrc_put *prsrc;
 
 	prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
 	if (!prsrc)
 		return -ENOMEM;
 
-	prsrc->tag = *io_get_tag_slot(data, idx);
+	prsrc->tag = *tag_slot;
+	*tag_slot = 0;
 	prsrc->rsrc = rsrc;
 	list_add(&prsrc->list, &node->rsrc_list);
 	return 0;
-- 
2.35.1