io_uring: zero tag on rsrc removal

[ 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>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index cc0a07a..ca207e9 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8413,13 +8413,15 @@ 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;