The patch below does not apply to the 5.6-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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 4518a3cc273cf82efdd36522fb1f13baad173c70 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Date: Tue, 26 May 2020 20:34:02 +0300
Subject: [PATCH] io_uring: fix flush req->refs underflow
In io_uring_cancel_files(), after refcount_sub_and_test() leaves 0
req->refs, it calls io_put_req(), which would also put a ref. Call
io_free_req() instead.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 2ca10259b418 ("io_uring: prune request from overflow list on flush")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0b51f21e5432..37422fcdaa7f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7534,7 +7534,7 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
* all we had, then we're done with this request.
*/
if (refcount_sub_and_test(2, &cancel_req->refs)) {
- io_put_req(cancel_req);
+ io_free_req(cancel_req);
finish_wait(&ctx->inflight_wait, &wait);
continue;
}
