[PATCH] media: mediatek: vpu: free IRQ before destroying watchdog workqueue

[Fan Wu]

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 at vger.kernel.org
Co-developed-by: Song Li <songl at zju.edu.cn>
Signed-off-by: Song Li <songl at zju.edu.cn>
Signed-off-by: Fan Wu <fanwu01 at zju.edu.cn>
---
 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 8d8319f..b6bd80b 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);