FAILED: patch "[PATCH] io_uring/zcrx: fix area release on registration failure" failed to apply to 6.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.15-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 <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.15.y
git checkout FETCH_HEAD
git cherry-pick -x 0ec33c81d9c7342f03864101ddb2e717a0cce03e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025062018-ahead-armory-59ac@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 0ec33c81d9c7342f03864101ddb2e717a0cce03e Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 27 May 2025 18:07:33 +0100
Subject: [PATCH] io_uring/zcrx: fix area release on registration failure

On area registration failure there might be no ifq set and it's not safe
to access area->ifq in the release path without checking it first.

Cc: stable@vger.kernel.org
Fixes: f12ecf5e1c5ec ("io_uring/zcrx: fix late dma unmap for a dead dev")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bc02878678a5fec28bc77d33355cdba735418484.1748365640.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 0c5b7d8f8d67..21c816c3bfe0 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -366,7 +366,8 @@ static void io_free_rbuf_ring(struct io_zcrx_ifq *ifq)
 
 static void io_zcrx_free_area(struct io_zcrx_area *area)
 {
-	io_zcrx_unmap_area(area->ifq, area);
+	if (area->ifq)
+		io_zcrx_unmap_area(area->ifq, area);
 	io_release_area_mem(&area->mem);
 
 	kvfree(area->freelist);