FAILED: patch "[PATCH] io_uring: fix leaks on IOPOLL and CQE_SKIP" failed to apply to 5.17-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.17-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@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c0713540f6d55c53dca65baaead55a5a8b20552d Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Sun, 17 Apr 2022 10:10:34 +0100
Subject: [PATCH] io_uring: fix leaks on IOPOLL and CQE_SKIP

If all completed requests in io_do_iopoll() were marked with
REQ_F_CQE_SKIP, we'll not only skip CQE posting but also
io_free_batch_list() leaking memory and resources.

Move @nr_events increment before REQ_F_CQE_SKIP check. We'll potentially
return the value greater than the real one, but iopolling will deal with
it and the userspace will re-iopoll if needed. In anyway, I don't think
there are many use cases for REQ_F_CQE_SKIP + IOPOLL.

Fixes: 83a13a4181b0e ("io_uring: tweak iopoll CQE_SKIP event counting")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5072fc8693fbfd595f89e5d4305bfcfd5d2f0a64.1650186611.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 24409dd07239..7625b29153b9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2797,11 +2797,10 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
 		/* order with io_complete_rw_iopoll(), e.g. ->result updates */
 		if (!smp_load_acquire(&req->iopoll_completed))
 			break;
+		nr_events++;
 		if (unlikely(req->flags & REQ_F_CQE_SKIP))
 			continue;
-
 		__io_fill_cqe_req(req, req->result, io_put_kbuf(req, 0));
-		nr_events++;
 	}
 
 	if (unlikely(!nr_events))