io_uring: fix mismatched finish_wait() calls in io_uring_cancel_files()

commit d8f1b9716cfd1a1f74c0fedad40c5f65a25aa208 upstream.

The prepare_to_wait() and finish_wait() calls in io_uring_cancel_files()
are mismatched. Currently I don't see any issues related this bug, just
find it by learning codes.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 043421f60ea6404328599c5a848ab94dc6e467b7..38052da4fdc5210c15d1f7e9d5ce531ae81b1b09 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6488,11 +6488,9 @@ static int io_uring_release(struct inode *inode, struct file *file)
 static void io_uring_cancel_files(struct io_ring_ctx *ctx,
                                  struct files_struct *files)
 {
-       struct io_kiocb *req;
-       DEFINE_WAIT(wait);
-
        while (!list_empty_careful(&ctx->inflight_list)) {
-               struct io_kiocb *cancel_req = NULL;
+               struct io_kiocb *cancel_req = NULL, *req;
+               DEFINE_WAIT(wait);
 
                spin_lock_irq(&ctx->inflight_lock);
                list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
@@ -6532,6 +6530,7 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
                         */
                        if (refcount_sub_and_test(2, &cancel_req->refs)) {
                                io_put_req(cancel_req);
+                               finish_wait(&ctx->inflight_wait, &wait);
                                continue;
                        }
                }
@@ -6539,8 +6538,8 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
                io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
                io_put_req(cancel_req);
                schedule();
+               finish_wait(&ctx->inflight_wait, &wait);
        }
-       finish_wait(&ctx->inflight_wait, &wait);
 }
 
 static int io_uring_flush(struct file *file, void *data)