FAILED: patch "[PATCH] media: mediatek: vpu: free IRQ before destroying watchdog workqueue" failed to apply to 5.15-stable tree

[Sasha Levin <sashal@kernel.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 2c50b58d4105f6dbaa36d6306087954b9100e9ae
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107060149-failed-5.15-2c50b58d4105@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

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

From 2c50b58d4105f6dbaa36d6306087954b9100e9ae Mon Sep 17 00:00:00 2001
From: Fan Wu <fanwu01@zju.edu.cn>
Date: Wed, 23 Sep 2026 08:59:21 +0000
Subject: [PATCH] media: mediatek: vpu: free IRQ before destroying watchdog
 workqueue

mtk_vpu_remove() destroys the watchdog workqueue while the interrupt
handler requested with devm_request_irq() is still registered: the
devres core frees the interrupt only after remove() has returned. If
the VPU watchdog fires in that window, vpu_irq_handler() queues
vpu->wdt.ws on the already destroyed vpu->wdt.wq.

Fix this by calling devm_free_irq() before destroy_workqueue(), which
releases the interrupt and waits for a running handler, so no new work
can be queued while the workqueue is drained and freed.

This issue was found by an in-house static analysis tool.

Fixes: 3003a180ef6b ("[media] VPU: mediatek: support Mediatek VPU")
Cc: stable@vger.kernel.org
Co-developed-by: Song Li <songl@zju.edu.cn>
Signed-off-by: Song Li <songl@zju.edu.cn>
Signed-off-by: Fan Wu <fanwu01@zju.edu.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/mediatek/vpu/mtk_vpu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/media/platform/mediatek/vpu/mtk_vpu.c b/drivers/media/platform/mediatek/vpu/mtk_vpu.c
index 8d8319f0cd221..b6bd80b684459 100644
--- a/drivers/media/platform/mediatek/vpu/mtk_vpu.c
+++ b/drivers/media/platform/mediatek/vpu/mtk_vpu.c
@@ -962,6 +962,7 @@ static void mtk_vpu_remove(struct platform_device *pdev)
 #ifdef CONFIG_DEBUG_FS
 	debugfs_remove(vpu_debugfs);
 #endif
+	devm_free_irq(&pdev->dev, vpu->reg.irq, vpu);
 	if (vpu->wdt.wq)
 		destroy_workqueue(vpu->wdt.wq);
 	vpu_free_ext_mem(vpu, P_FW);
-- 
2.53.0