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;