FAILED: patch "[PATCH] media: samsung: exynos4-is: fix potential ABBA deadlock on" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

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 <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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 17dc8ccd6dd5ffe30aa9b0d36e2af1389344ce2b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026010542-mockup-flagstone-535a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 17dc8ccd6dd5ffe30aa9b0d36e2af1389344ce2b Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Tue, 14 Oct 2025 12:46:43 +0200
Subject: [PATCH] media: samsung: exynos4-is: fix potential ABBA deadlock on
 init

v4l2_device_register_subdev_nodes() must called without taking
media_dev->graph_mutex to avoid potential AB-BA deadlock on further
subdevice driver initialization.

Fixes: fa91f1056f17 ("[media] exynos4-is: Add support for asynchronous subdevices registration")
Cc: stable@vger.kernel.org
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

diff --git a/drivers/media/platform/samsung/exynos4-is/media-dev.c b/drivers/media/platform/samsung/exynos4-is/media-dev.c
index d6f7601de597..bc7087eb761a 100644
--- a/drivers/media/platform/samsung/exynos4-is/media-dev.c
+++ b/drivers/media/platform/samsung/exynos4-is/media-dev.c
@@ -1399,12 +1399,14 @@ static int subdev_notifier_complete(struct v4l2_async_notifier *notifier)
 	mutex_lock(&fmd->media_dev.graph_mutex);
 
 	ret = fimc_md_create_links(fmd);
-	if (ret < 0)
-		goto unlock;
+	if (ret < 0) {
+		mutex_unlock(&fmd->media_dev.graph_mutex);
+		return ret;
+	}
+
+	mutex_unlock(&fmd->media_dev.graph_mutex);
 
 	ret = v4l2_device_register_subdev_nodes(&fmd->v4l2_dev);
-unlock:
-	mutex_unlock(&fmd->media_dev.graph_mutex);
 	if (ret < 0)
 		return ret;