FAILED: patch "[PATCH] io_uring: fix double poll leak on repolling" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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 <[email protected]>.

Possible dependencies:

c0737fa9a5a5 ("io_uring: fix double poll leak on repolling")
10c873334feb ("io_uring: allow re-poll if we made progress")
52dd86406dfa ("io_uring: enable EPOLLEXCLUSIVE for accept poll")
4d9237e32c5d ("io_uring: recycle apoll_poll entries")
cc3cec8367cb ("io_uring: speedup provided buffer handling")
d5ec1dfaf59b ("io-uring: add __fill_cqe function")
77bc59b49817 ("io_uring: avoid ring quiesce while registering/unregistering eventfd") 0d7c1153d929 ("io_uring: Clean up a false-positive warning from GCC 9.3.0") 42a7b4ed45e7 ("Merge tag 'for-5.17/io_uring-2022-01-11' of git://git.kernel.dk/linux-block")

thanks,

greg k-h

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

From c0737fa9a5a5cf5a053bcc983f72d58919b997c6 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <[email protected]>
Date: Wed, 22 Jun 2022 00:00:37 +0100
Subject: [PATCH] io_uring: fix double poll leak on repolling

We have re-polling for partial IO, so a request can be polled twice. If it used two poll entries the first time then on the second io_arm_poll_handler() it will find the old apoll entry and NULL kmalloc()'ed second entry, i.e. apoll->double_poll, so leaking it.

index cb719a53b8bd..5c95755619e2 100644
@@ -7208,6 +7208,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
 		mask |= EPOLLEXCLUSIVE;
 	if (req->flags & REQ_F_POLLED) {
 		apoll = req->apoll;
+		kfree(apoll->double_poll);
 	} else if (!(issue_flags & IO_URING_F_UNLOCKED) &&
 		   !list_empty(&ctx->apoll_cache)) {
 		apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,