FAILED: patch "[PATCH] media: chips-media: wave5: Handle polling IRQ thread failure" failed to apply to 6.12-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.12-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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 1d563e3d718a1c7c16355843374fbdd4c798ac66
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107051848-failed-6.12-1d563e3d718a@kernel.org' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Thanks,
Sasha

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

From 1d563e3d718a1c7c16355843374fbdd4c798ac66 Mon Sep 17 00:00:00 2001
From: Linmao Li <lilinmao@kylinos.cn>
Date: Fri, 17 Jul 2026 15:13:15 +0800
Subject: [PATCH] media: chips-media: wave5: Handle polling IRQ thread failure

When falling back to polling mode, wave5_vpu_probe() does not check the
return value of kthread_run().  On failure, dev->irq_thread holds an
error pointer instead of a valid task pointer.

Both the probe error path and the remove path only check
dev->irq_thread against NULL before calling kthread_stop() on it, so an
error pointer passes the check and kthread_stop() crashes on it.

Check the kthread_run() result, clear dev->irq_thread and unwind the
probe on failure.

Fixes: e66ff2b08e4e ("media: chips-media: wave5: Fix Null reference while testing fluster")
Cc: stable@vger.kernel.org
Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
---
 drivers/media/platform/chips-media/wave5/wave5-vpu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu.c b/drivers/media/platform/chips-media/wave5/wave5-vpu.c
index 76d57c6b636a2..37df270b5f991 100644
--- a/drivers/media/platform/chips-media/wave5/wave5-vpu.c
+++ b/drivers/media/platform/chips-media/wave5/wave5-vpu.c
@@ -340,6 +340,13 @@ static int wave5_vpu_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "failed to get irq resource, falling back to polling\n");
 		sema_init(&dev->irq_sem, 1);
 		dev->irq_thread = kthread_run(irq_thread, dev, "irq thread");
+		if (IS_ERR(dev->irq_thread)) {
+			ret = PTR_ERR(dev->irq_thread);
+			dev_err(&pdev->dev, "failed to create irq thread\n");
+			dev->irq_thread = NULL;
+			goto err_vdi_release;
+		}
+
 		hrtimer_setup(&dev->hrtimer, &wave5_vpu_timer_callback, CLOCK_MONOTONIC,
 			      HRTIMER_MODE_REL_PINNED);
 		dev->worker = kthread_run_worker(0, "vpu_irq_thread");
-- 
2.53.0